One problem that seems to happen sometimes to a Windows XP Box is that it will start really slowing down and be ready for a reimage. There is a way around this and it involves the repair tool on the Windows XP CD. Here are some steps.
1. Boot up with a Windows XP CD with XP 2
2. after the initial startup, wait until it asks you if you want to do an install or repair, choose a new install
3. Windows XP checks through your drives and finds your current install. NOW choose the repair option.
4. Windows will reload itself and prompt for some of the stuff you would have in a regular install including your CD Key, regional settings and maybe some drivers.
5. After a restart your computer will boot up just as it was before. Even your desktop should be there.
This non repair repair install is good for refreshing the operating system but it does not delete your profile in the same way that doing a repair or a new install would delete your profile and settings.
After doing this process today I found that my Windows XP was a lot more responsive but all of my applications and settings were still good. See if this works and if not try reinstalling Windows from scratch as I have documented on another site but will put here on another post