The prefetch directory under %WINDIR%

Windows XP (and its successors) contains a directory named prefetch in the %WINDIR% (usually something like C:\windws.

As discussed in this article, windows' prefetch manager monitors which files are used at startup and application starts.

When Windows starts, it opens those files and brings them into memory in such order that the heads of the harddisk have a minimal moving, thus reducing the time needed to boot and start applications.

The name of these files consist of two parts: the name of the application that uses it and a hashed version of the file path, for example: PERL.EXE-1300F3C0.pf. The suffix is pf.