Over time, Windows loses stability. If you keep a computer for more than two years, at some point you're going to have to bite the bullet and reinstall Windows from scratch. But contrary to popular belief, you won't have to reformat your hard drive (with one exception, discussed below). The bad stuff you need to get rid of is all in your Windows folder.

Before you begin, gather your Windows and application CD-ROMs. Back up your data files (just to be safe), and then clear two days off your calendar. If everything goes smoothly, you can reinstall Windows in a few hours. But you have to assume something will go wrong: You may not be able to find a necessary CD, or data won't be where you thought it was, or something will simply refuse to work.

There's a difference between a repair reinstall and a complete reinstall. Though a repair (also called a refresh) will let you keep your current settings, a complete reinstall will give you a truly fresh version of Windows. Repairs are fast and easy, but they don't fix anywhere near as many problems. The instructions below are for total reinstalls, except where noted.

Your Vendor's Restore CD
Most computers ship with a vendor-specific restore CD rather than with a Microsoft Windows CD-ROM. (If your PC came with a Microsoft Windows CD, or if you bought a retail copy of Windows, skip to the section for your version.)

Some restore CDs give you all the options of a full Microsoft Windows CD, but with better instructions and the convenience of having all the right hardware drivers. Others can do nothing except reformat your hard