XP Search FIX:

Using the "a word or phrase in the file" search criterion may not work in XP's file search. But you can actually fix it yourself! To fix it, follow these instructions:

Using the registry editor (Start->Run->regedit), change this setting:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ContentIndex

It's default value for the key FilterFilesWithUnknownExtensions is 0 (zero). Set it to 1 (one).