My XP computer is 7years old start up is slow and I have done things like stopped programs loading at startup with msconfig and have defragged repaired the registry and used CC cleaner when I have finished useing my computer,I have Super Anti Spyweare program to look for viruses.I just wondered if it was time to buy a new pc.

This is as good a reason as any to buy a new PC. Get one now with Windows 7 and have fun. I'm running it on my Dell Precision 370 and like it very much. XP seems old and boring now, though they took away some things I really miss in Win 7, but not enough that I can't do without.

Otherwise, backup your personal data then do a clean install of XP or restore to factory state. That will most likely get your computer running like it did when you first bought it, unless there is a hardware problem (hard drive, memory, video card).

Do you have a XP Install CD or did the computer come with recovery CDs?

If you have already upgraded your RAM to 1Gb or more, and have a decent graphics solution and you are still not satisfied (assuming everything is working correctly and your system is clean of malware), then I agree, it is time to budget for a new computer with more current specifications that are made to deal with today's computing, especially graphics, demands.