I saw david hess tweak which is delete prefetch automatically, but you only have to put /q after "del C:\Windows\Prefetch\*.*" to make it really automatic!
like he said,
create a new text file
type "del c:\windows\prefetch\*.* /q"
save the file as "whateverthename.bat"
whoalla, a batch file for deleting prefetch
automatically, now it is really automatic.
Note from forum Admin: First, it's easy enough to go to the \Windows\Prefetch folder and manually delete the files. But I recommend against deleting Prefetch folder files more than once a month or so - otherwise you are defeting the purpose of the cache.