Monday, 24 March 2014
Best 802.11ac routers
The 802.11ac Wi-Fi standard (aka 5G Wi-Fi) is the latest on the market and offers up to 1.3Gbps of wireless connection speed. First introduced during CES 2012, the new standard can now be found in many routers. These routers, for backward compatibility, also come with Wireless-N (802.11n) and hence support all existing Wi-Fi clients. Hardware clients that are 802.11ac-capable, however, are still very scarce on the market. Following are the top routers that support the new 802.11ac standard on the market. Since there are not many of them, all of those on this list are the best of their kind.
How to Create/restore a restore point in Windows XP
Before starting we must understand what actually restore point is basically it is
A restore point is a date and time in the past that you can restore important Windows files to using the System Restore tool.
Setting a restore point lets you select a point in time when your computer is working as you want. Then, you can use the restore point to undo any unwanted changes to your computer in the future.
This method is rated: Easy.
To set up a restore point, follow these steps:
- Close any programs that are open.
- Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore. The System Restore Wizard opens.
Note If the System Restore Wizard does not open, the System Restore feature may be turned off. To turn System Restore on, see the "More Information" section in this article. - Click Create a restore point, and then click Next.
- In Restore point description
box, type a description for the restore point. Use a description that
is easy to understand. If you are creating a restore point before you
install specific software or hardware, you could use that information in
the description.
Note The date and time are automatically added to your restore point. Therefore, you do not have to use them in your description. - Do one of the following:
- To finish creating this restore point, click the Create button. The System Restore Wizard notifies you when the restore point is created.
- To stop creating a restore point and to return to the Welcome to System Restore page, click the Back button.
- To stop creating a restore point and to exit the System Restore Wizard, click the Cancel button.
- When you are finished, click the Close button.
Notes
- Windows XP automatically creates system restore points every day. Typically, it creates restore points before a program or a hardware device is installed.
- If you install a program, but then later you use a restore point that was created before you installed that program, the program will no longer work. If you want to use the program again, you must reinstall it.
- System Restore differs from uninstalling a program. To completely remove a program, you must remove the program by using Add or Remove Programs in Control Panel or by using the program's own uninstall program. For more information, search for the help topic "Change or remove a program" in Windows XP Help and Support.
Restore point verification
To view the restore point, repeat step 2. Then, in the Welcome to System Restore page of the System Restore Wizard, select Restore my computer to an earlier time, and then click Next. Then select the date when the restore point was created from the calendar on the Select a Restore Point page. All the restore points that were created on the selected date are listed by name in the list box on the right side of the calendar.If this method worked
If the system restore point is created, you are finished!How to use System Restore to restore Windows XP to a previous state
To use System Restore to restore Windows XP to a previous state, follow these steps:
If the restore process completed successfully but the computer does not run as expected, go to the "How to undo a system restoration after you perform a System Restore" section. If you received an error message, and the restore process was not completed, or if you cannot run System Restore, go to the "Next Steps" section.
- Log on to Windows as an administrator.
- Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore. (The screen shot for this step is listed below).
- On the Welcome to System Restore page, click to select the Restore my computer to an earlier time option, and then click Next. (The screen shot for this step is listed below).
- On the Select a Restore Point page, click the most recent system restore point in the On this list, click a restore point list, and then click Next.Note A System Restore message may appear that lists configuration changes that System Restore will make. Click OK. (The screen shot for this step is listed below).
- On the Confirm Restore Point Selection page, click Next. System Restore restores the previous Windows XP configuration, and then restarts the computer.
- Log on to the computer as an administrator. Then, click OK on the System Restore Restoration Complete page. (The screen shot for this step is listed below).
If the restore process completed successfully but the computer does not run as expected, go to the "How to undo a system restoration after you perform a System Restore" section. If you received an error message, and the restore process was not completed, or if you cannot run System Restore, go to the "Next Steps" section.
How to undo a system restoration after you perform a System Restore
You may have unintentionally restored Windows XP to a previous
configuration that you do not want. To undo the restoration, follow
these steps:
- Log on to Windows as an administrator.
- Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore. (The screen shot for this step is listed below).
- On the Welcome to System Restore page, click to select the Undo my last restoration option, and then click Next. Note A System Restore message may appear that lists configuration changes that System Restore will make. Click OK. (The screen shot for this step is listed below).
- On the Confirm Restoration Undo page, click Next. System Restore restores the original Windows XP configuration and then restarts the computer.
- Log on to the computer as an administrator. The System Restore Undo Complete page appears. (The screen shot for this step is listed below).
- Click OK. You can now run System Restore again from a different restore point.
Saturday, 22 March 2014
How to Scan and Fix a Hard Drive-CHKDSK Utility
Find the CHKDSK Utility
- Click on the Start Menu; click My Computer.
- Right-click on the hard drive and select Properties. Start the CHKDSK Utility
- Select the Tools Tab and click Check Now.
- At the Check Disk menu, click both options (to “Automatically fix file system errors” and “Scan for and attempt recovery of bad sectors”).
- Click Start. Schedule the Utility to Check the DiskA message will ask you if you want to schedule a disk check, click Yes.Restart Your Computer, Run CHKDSK
- Close all open menus and programs.
- Restart your computer.
Note:It may take an hour or two to do this test, so do not perform this test when you have insufficient time.
PARTS OF COMPUTER
If you use a desktop computer, you might already know
that there isn't any single part called the "computer." A computer is
really a system of many parts working together. The physical parts,
which you can see and touch, are collectively called hardware. (Software, on the other hand, refers to the instructions, or programs, that tell the hardware what to do.)
The following illustration shows the most common
hardware in a desktop computer system. Your system might look a little
different, but it probably has most of these parts. A laptop computer
has similar parts but combines them into a single, notebook-sized
package.
Let's take a look at each of these parts.
System unit
The system unit is
the core of a computer system. Usually it's a rectangular box placed on
or underneath your desk. Inside this box are many electronic components
that process information. The most important of these components is the central processing unit (CPU), or microprocessor, which acts as the "brain" of your computer. Another component is random access memory (RAM),
which temporarily stores information that the CPU uses while the
computer is on. The information stored in RAM is erased when the
computer is turned off.
Almost every other part of your computer connects to the system unit using cables. The cables plug into specific ports (openings), typically on the back of the system unit. Hardware that is not part of the system unit is sometimes called a peripheral device or device.
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Storage
Your computer has one or more disk drives—devices
that store information on a metal or plastic disk. The disk preserves
the information even when your computer is turned off.
Hard disk drive
Your computer's hard disk drive stores information on a hard disk—a
rigid platter or stack of platters with a magnetic surface. Because
hard disks can hold massive amounts of information, they usually serve
as your computer's primary means of storage, holding almost all of your
programs and files. The hard disk drive is normally located inside the
system unit.
CD and DVD drives
Nearly all computers today come equipped
with a CD or DVD drive, usually located on the front of the system unit.
CD drives use lasers to read (retrieve) data from a CD; many CD drives
can also write (record) data onto CDs. If you have a recordable disk
drive, you can store copies of your files on blank CDs. You can also use
a CD drive to play music CDs on your computer.
DVD drives can do everything that CD drives
can, plus read DVDs. If you have a DVD drive, you can watch movies on
your computer. Many DVD drives can record data onto blank DVDs.
Tip
-
If you have a recordable CD or DVD drive, periodically back up (copy) your important files to CDs or DVDs. That way, if your hard disk ever fails, you won't lose your data.
Floppy disk drive
Floppy disk drives store information on floppy disks, also called floppies or diskettes.
Compared to CDs and DVDs, floppy disks can store only a small amount of
data. They also retrieve information more slowly and are more prone to
damage. For these reasons, floppy disk drives are less popular than they
used to be, although some computers still include them.
Why are these disks called "floppy" disks?
The outside is made of hard plastic, but that's just the sleeve. The
disk inside is made of a thin, flexible vinyl material.
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Mouse
A mouse is a small device used to point to and
select items on your computer screen. Although mice come in many shapes,
the typical mouse does look a bit like an actual mouse. It's small,
oblong, and connected to the system unit by a long wire that resembles a
tail. Some newer mice are wireless.
A mouse usually has two buttons: A primary
button (usually the left button) and a secondary button. Many mice also
have a wheel between the two buttons, which allows you to scroll
smoothly through screens of information.
When you move the mouse with your hand, a
pointer on your screen moves in the same direction. (The pointer's
appearance might change depending on where it's positioned on your
screen.) When you want to select an item, you point to the item and then
click (press and release) the primary
button. Pointing and clicking with your mouse is the main way to
interact with your computer. For more information, see Using your mouse.
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Keyboard
A keyboard is used mainly for typing text into
your computer. Like the keyboard on a typewriter, it has keys for
letters and numbers, but it also has special keys:
-
The function keys, found on the top row, perform different functions depending on where they are used.
-
The numeric keypad, located on the right side of most keyboards, allows you to enter numbers quickly.
-
The navigation keys, such as the arrow keys, allow you to move your position within a document or webpage.
You can also use your keyboard to perform many of the same tasks you can perform with a mouse. For more information, see Using your keyboard.
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Monitor
A monitor displays
information in visual form, using text and graphics. The portion of the
monitor that displays the information is called the screen. Like a television screen, a computer screen can show still or moving pictures.
There are two basic types of monitors: CRT (cathode ray tube) monitors and the newer LCD
(liquid crystal display) monitors. Both types produce sharp images, but
LCD monitors have the advantage of being much thinner and lighter.
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Printer
A printer transfers data from a computer onto
paper. You don't need a printer to use your computer, but having one
allows you to print e‑mail, cards, invitations, announcements, and other
material. Many people also like being able to print their own photos at
home.
The two main types of printers are inkjet printers and laser printers.
Inkjet printers are the most popular printers for the home. They can
print in black and white or in full color and can produce high-quality
photographs when used with special paper. Laser printers are faster and
generally better able to handle heavy use.
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Speakers
Speakers are used to play sound. They can be
built into the system unit or connected with cables. Speakers allow you
to listen to music and hear sound effects from your computer.
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Modem
To connect your computer to the Internet, you need a modem.
A modem is a device that sends and receives computer information over a
telephone line or high-speed cable. Modems are sometimes built into the
system unit, but higher-speed modems are usually separate components.
Steps to Speed Up Your Computer’s Performance
1. Make Sure Your Hardware is Sufficient
Above and beyond everything you can do with software to optimize the function of your computer, making sure you have the proper hardware to support Windows is critical.2. Clean Your Desktop
Is your Windows Desktop dotted with files? Have you noticed that your computer has been running slower and slower? Do you see the hard drive light often flashing while you wait for the computer to respond to an action? There are steps you can take to fix it. Read this article.3. Scan Your Windows System for Errors
An operating system is a collection of files that perform different functions. It is possible, over time, that one or more of these system files has changed or become corrupted. If this happens, the speed of your system may decrease. By using a utility called “System File Checking”, it will inspect these files and correct any problem it finds.4. Scan for Viruses, Spyware and Adware
Every Windows computer is vulnerable to viruses. Viruses are nasty little programs that cause both major and minor problems for users.Spyware and Adware are programs created by companies to find out more information about customers, so they can better market products to them. Usually these programs are not created for malicious purposes. Spyware and Adware can load into computer memory and slow it down.
Periodically scanning and removal of Viruses, Spyware and Adware is a great way to improve computer performance.
5. Uninstall Unused Programs
Over time, you may have accumulated programs on your computer that you do not use. When a program is installed, it creates connections between the program and the operating system. Even if you don’t use these programs, they can slow down your system. If you have the original program’s installation disk or file, removing programs will free up space on your computer and may speed up your system's performance.6. Adjust Visual Effects for Better Performance
Windows provides a number of interesting visual effects including animated windows and fading menus. If you do not have enough operating memory (see above number 1), these effects can slow down your computer. Adjusting or reducing visual effects can make a difference.To speed up Vista computers in particular you can disable features and function that are not used. For more information, read
7. Don’t Automatically Start Programs
Programs use operating memory (RAM, also called system resources). Unless you always use these programs, you can keep them from loading at Windows startup and speed both the booting of your computer and its performance.8. De fragment Your Hard Drive (After you have tried everything else)
The more information and programs you have on your computer, the more it is likely that Windows has placed parts of the same file in different locations on your hard drive. It may do this for hundreds of files and programs, depending on how much space is available. Defragmenting the hard drive places all information for each file in one place. The result can be a faster computer experience.Important Note: Before you even try this, backup all your work onto a different computer, hard drive, CD or disk. Also, you should only do this if you have a reliable source of power for your computer. Doing this when there is a brown out or power problem in the neighborhood, is not a good idea. If a computer turns off while it is defragmenting a drive, it will create more problems than not defragmenting it in the first place.
9. Reinstall the Operating System and Programs
If you have done all the above steps and your computer does not become more responsive, you might consider reinstalling the operating system and programs. This is a scorched earth option - basically you backup all your data and user settings, wipe your hard drive clean and re-install the operating system with your original disks. Next, install all your favorite programs and restore all your data and user settings.The nice thing about doing this is that you essentially have a new computer, free of years worth of software and registry changes, additions and errors that can turn a fast rabbit of a Windows computer into a slow turtle. The bad thing about this choice is that it takes time and planning to do it correctly. If your PC is 3 to 4 years old and continues to run slower than it did when you purchased it, this might be the only action that will make a significant difference.
INTRODUCTION ABOUT COMPUTER
What are computers?
Computers are machines that perform tasks or calculations according to a set of instructions, or programs.
The first fully electronic computers, introduced in the 1940s, were
huge machines that required teams of people to operate. Compared to
those early machines, today's computers are amazing. Not only are they
thousands of times faster, they can fit on your desk, on your lap, or
even in your pocket.
Computers work through an interaction of hardware and software. Hardware
refers to the parts of a computer that you can see and touch, including
the case and everything inside it. The most important piece of hardware
is a tiny rectangular chip inside your computer called the central processing unit (CPU), or microprocessor.
It's the "brain" of your computer—the part that translates instructions
and performs calculations. Hardware items such as your monitor,
keyboard, mouse, printer, and other components are often called hardware devices, or devices.
Software refers to the
instructions, or programs, that tell the hardware what to do. A
word-processing program that you can use to write letters on your
computer is a type of software. The operating system (OS) is software
that manages your computer and the devices connected to it. Windows is a
well-known operating system.
Types of computers
Computers range in size and capability. At one end of the scale are supercomputers,
very large computers with thousands of linked microprocessors that
perform extremely complex calculations. At the other end are tiny
computers embedded in cars, TVs, stereo systems, calculators, and
appliances. These computers are built to perform a limited number of
tasks.
The personal computer, or PC,
is designed to be used by one person at a time. This section describes
the various kinds of personal computers: desktops, laptops, handheld
computers, and Tablet PCs.
Desktop computers
Desktop computers are
designed for use at a desk or table. They are typically larger and more
powerful than other types of personal computers. Desktop computers are
made up of separate components. The main component, called the system unit,
is usually a rectangular case that sits on or underneath a desk. Other
components, such as the monitor, mouse, and keyboard, connect to the
system unit.
Laptops and netbooks
Laptops are lightweight
mobile PCs with a thin screen. Laptops can operate on batteries, so you
can take them anywhere. Unlike desktops, laptops combine the CPU,
screen, and keyboard in a single case. The screen folds down onto the
keyboard when not in use.
Netbooks (also referred to as mini notebooks),
are small, affordable laptops that are designed to perform a limited
number of tasks. They're usually less powerful than laptops, so they're
used mainly to browse the web and check e‑mail.
Smartphones
Smartphones are mobile phones
that have some of the same capabilities as a computer. You can use a
smartphone to make telephone calls, access the Internet, organize
contact information, send e‑mail and text messages, play games, and
take pictures. Smartphones usually have a keyboard and a large screen.
Handheld computers
Handheld computers, also called personal digital assistants (PDAs),
are battery-powered computers small enough to carry almost anywhere.
Although not as powerful as desktops or laptops, handheld computers are
useful for scheduling appointments, storing addresses and phone numbers,
and playing games. Some have more advanced capabilities, such as making
telephone calls or accessing the Internet. Instead of keyboards,
handheld computers have touch screens that you use with your finger or a
stylus (a pen-shaped pointing tool).
Tablet PCs
Tablet PCs are mobile PCs
that combine features of laptops and handheld computers. Like laptops,
they're powerful and have a built-in screen. Like handheld computers,
they allow you to write notes or draw pictures on the screen, usually
with a tablet pen instead of a stylus. They can also convert your
handwriting into typed text. Some Tablet PCs are “convertibles” with a
screen that swivels and unfolds to reveal a keyboard underneath.
What can you do with computers?
In the workplace, many people use computers to
keep records, analyze data, do research, and manage projects. At home,
you can use computers to find information, store pictures and music,
track finances, play games, and communicate with others—and those are
just a few of the possibilities.
You can also use your computer to connect to the Internet,
a network that links computers around the world. Internet access is
available for a monthly fee in most urban areas, and increasingly, in
less populated areas. With Internet access, you can communicate with
people all over the world and find a vast amount of information.
Here are some of the most popular things to do with computers:
The web
The World Wide Web (usually called the web, or web)
is a gigantic storehouse of information. The web is the most popular
part of the Internet, partly because it displays most information in a
visually appealing format. Headlines, text, and pictures can be combined
on a single webpage—much like a page in a magazine—along with sounds and animation. A website is a collection of interconnected webpages. The web contains millions of websites and billions of webpages.
Surfing the web means
exploring it. You can find information on the web about almost any topic
imaginable. For example, you can read news stories and movie reviews,
check airline schedules, see street maps, get the weather forecast for
your city, or research a health condition. Most companies, agencies,
museums, and libraries have websites with information about their
products, services, or collections. Reference sources, such as
dictionaries and encyclopedias, are also widely available.
The web is also a shopper's delight. You can
browse and purchase products—books, music, toys, clothing, electronics,
and much more—at the websites of major retailers. You can also buy and
sell used items through websites that use auction-style bidding.
E‑mail
E‑mail (short for electronic mail)
is a convenient way to communicate with others. When you send an e‑mail
message, it arrives almost instantly in the recipient's e‑mail inbox.
You can send e‑mail to many people simultaneously, and you can save,
print, and forward e‑mail to others. You can send almost any type of
file in an e‑mail message, including documents, pictures, and music
files. And with e‑mail, you don't need a postage stamp!
Instant messaging
Instant messaging is like having a real-time
conversation with another person or a group of people. When you type
and send an instant message, the message is immediately visible to all
participants. Unlike e‑mail, all participants have to be online
(connected to the Internet) and in front of their computers at the same
time. Communicating by means of instant messaging is called chatting.
Pictures, music, and movies
If you have a digital camera, you can move
your pictures from the camera to your computer. Then you can print them,
create slide shows, or share them with others by e‑mail or by posting
them on a website. You can also listen to music on your computer, either
by importing music from audio CDs or by purchasing songs from a music
website. Or, you can tune in to one of the thousands of radio stations
that broadcast over the Internet. If your computer comes with a DVD
player, you can watch movies too.
Gaming
Do you like to play games? Thousands of computer games in every conceivable category are available to entertain you. Get behind the wheel of a car, battle frightening creatures in a dungeon, or control civilizations and empires! Many games allow you to compete with other players around the world through the Internet. Windows includes a variety of card games, puzzle games, and strategy games.What are computers?
Computer is machine that perform tasks or calculations according to a set of instructions, or programs.
(Ferranti Pegasus computer)
First Generation Of Computers
The first fully electronic computers, introduced in the 1940s, were
huge machines (as shown above) that required teams of people to operate.
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