This is my short and not-so-specific method of reformatting. I may rewrite it in the future and add details.

If your computer has a virus/worm/trojan, if it's running much slower than usual, or if it keeps reporting errors, you may want to reformat your computer. Reformatting usually does the trick. Just keep in mind that in the process of reformatting, everything on your hard drive is erased. So, you are well advised not do so unless you can backup your necessary files or continue if you have no files that need to be backed up.

You then have the option of installing an operating system if you have the disc and a license to do so. Example: Windows Vista, Windows XP, etc. Be sure your computer physically meets the requirements to run the desired operating system. Example: Windows XP requires 128mb of RAM to run successfully, while Windows Vista requires 1gb of RAM. If all goes as planned, you're left with a brand new computer. Yay.

But, it's not over yet. In order for your computer to run the way it's supposed to, you're going to need drivers. Think of drivers as small programs that teach your computer how to use certain physical parts of your computer. There's usually a driver for your sound card, graphics card, motherboard, network card, disc drives, web cams, and more. Needless to say, if you don't have the drivers installed, you won't have sound, video, internet, etc.

Make sure these drivers exist for the operating system you're installing, and have them available on a USB drive before you begin the reformatting process.
I cannot express this enough!

If you're going to install an older operating system like Windows XP, it may be harder to find these drivers as most companies like HP no longer support it. The truth is, Windows Vista and Windows 7 are the future. There is no reason to take a step back when we can take one, or two, steps forward. Some would disagree with this concept, but the money-making companies simply don't care.

If perchance, the drivers you seek are not available from the manufacturer's website, you may be able to find them elsewhere if someone has made them. If you decide to install consumer-created drivers, be sure to read reviews and comments for the specified drivers, and make sure they've received positive feedback. If you can't find the most recent version of the driver you're looking for, you can use an older one just the same. Chances are, you won't even notice the difference.

Once all your drivers are installed, you're good to go. One other thing I like to do is download the latest service pack. For example, if you installed Windows XP, you can download Service Pack 3 from the Microsoft Website. If you installed Windows Vista, you can download Service Pack 2. With these installed, you can be sure your computer is running as fast as it should. As part of the service packs, you're usually given an updated firewall for security, and the latest internet browser. What more can you ask for?

Let me know if you have any questions. You can reach me through my contact page. Good luck and happy reformatting!