Windows XP can load programs it thinks you need before you actually load them yourself! This is done by a process called pre-fetching. This process can consume memory and slow your XP experience.

Windows XP will retain a copy of a portion of a program you have run in the prefetch folder even if you only used it once. If you are unlikely to use this program again, this will adversely affect the performance of your system and is of no benefit to you!

You can see the contents of the prefetch directory by navigating to %systemroot%\prefetch

If you would like to selectively remove programs from the prefetch folder, you can manually delete the items from within the directory listed above. If you would like to disable the service entirely however, please follow the instructions below.

Navigate to [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory] using regedit:

1. Find the EnablePrefetcher key
2. Set the EnablePrefetcher key to 0