A friend with little pc knowledge (and that's true) decided he would like to see the contents of a Prefetch file. For reasons which he cannot explain he has managed to set all .pf files to open with Acrobat Reader!!! How can the .pf files be reset to open with their programs please. BTW setting .pf files to open with Acrobat Reader doesn't seem to have affected performance. Thanks

I have read that Prefetch files are files that are stored at the outer edge of the harddrive, and are not moved during defrag. They aid in quick starting of programs. I have at times deleted all of the files, including Layout.ini, without any decrease in performance. I guess you can do the same, and watch it rebuild itself over time. ----------------- I think if you must fix it, then do this-- How to Perform an In-Place Upgrade (Reinstallation) of Windows XP You will lose Windows Updates and Shared Documents only.

Valerie, In addition to Chuck 2's explantion here's some more info. Prefetch files are essentially a resource list. Any time a program is executed, Windows XP will attempt to find a pre-existing prefetch file, and if it's available, it will use it to make the application load up faster. The file will also be updated after it is accessed, so that the more an application is used, the bigger the drop in loading time (to a point). If the application doesn't already have an associated prefetch file, Windows XP will create one. Those files are stored in the \%windir%\prefetch directory. One important note is that the process depends on the Task Scheduler service. If the Task Scheduler service isn't running, the prefetch mechanism isn't used and the files won't be read or updated. Personally, I wouldn't worry about your concern as there's really no need to read the Prefetch files and what your friend did shouldn't harm anything at all. This is only my opinion. Tufenuf

Many thanks guys - I guess we'll just ignore them. V...