A. Is Your PC Upgradable?

1. How old is your PC?

If your computer is less than a year old, upgrading to Windows XP should be easy. Things get iffier with PCs between one and two years old. If your PC is more than two years old, you're usually better off keeping what you have or buying a new PC with XP preinstalled.

2. Are you running an old version of Windows?

If you currently run Windows 95 or Windows 3.11, you're ineligible for the upgrade version of XP; instead, you'll need to buy a full-installation version ($199 for the Home version; $299 for Pro).

3. Consult your PC maker.

Many vendors' Web sites have a dedicated section containing XP-specific upgrade notes and advice. If there isn't one at your PC maker's site, go to the site's support section and search for your specific PC model. You may find (as shown here) that an XP upgrade isn't recommended. If your PC is home-built, proceed to steps four, five, and six.

4. Check your PC's hardware.

Though Microsoft recommends a minimum of a 300-MHz processor for Windows XP, you'll be happier with at least a 500-MHz CPU. Plus, you'll need no less than 128MB of RAM (256MB is better). And figure on setting aside at least 1.5GB of free hard-disk space.

5. Run the PCWorld.com XP Readiness Test.

PCWorld.com's XP Readiness Test, an interactive diagnostic test that PC World coproduced with PC Pitstop, will check your system to see how it stacks up for an XP upgrade and will recommend fixes if any are necessary.

6. Run the Upgrade Advisor.

For a comprehensive evaluation of your PC's XP compatibility, run Microsoft's Upgrade Advisor. It's included with all versions of XP. To check out your PC before you buy the full operating system, aim your browser and download the 50MB Upgrade Advisor. If you want to avoid the download time, ask a computer dealer; most have free Upgrade Advisor CDs available.