Windows XP caches frequent applications, services, and files in a folder called "prefetch" to speed the launching of these items. A problem with this is that XP isn't too smart about what it caches -- which includes one-time use setup files and Windows updates, as well as multiple copies of the same applications. This can lead to prefetch bloat and slower boot times.
However you can easily clean it. Choose Start, Run and then type prefetch. The prefetch folder will open and you can safely delete many of these unnecessary shortcuts such as updates, patches, temp files, etc. Afterwards, XP should start quicker (you may want to do a defrag or defrag -b to fully realize the benefits.
This was first published in October 2004