This is an unique technique for Windows XP. We know that it is necessary to wash registry and TEMP files for Win9X/ME/2000 period.

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 notability.

My suggestion is: open C: (system drive):/Windows/Prefetch, delete those junk and obsolete files, reboot. It is recommended that you do this every month.