I did not get any forum on this topic.. So decided to post here..

Prefetch is a new and very useful technique in Windows XP. However, after using XP some time, the prefetch directory can get full of junk and obsolete links in the Prefetch catalog, which can slow down your computer noticeably. I would suggest that You do this once a month: Go to C(system drive):/windows/prefetch, and delete everything and reboot. This may help speed up your computer.

Yep. You should clean it if you have uninstalled a few software otherwise no need to clear the contents.

Hey even i tried it on vista only.. and i have been using ccleaner, it works perfecftly..