Windows XP Search tool can be very useful for finding files on your computer, and if you want to find a file that contains a particular word or phrase you can enter it in the box provided. However if you are running Windows XP you may be out of luck because for some reason Microsoft decided that by default it will only search in certain file types in order to improve performance.
There is a quick solution to this problem though.
All you have to do is run regedit.exe and navigate the tree to :
FilterFilesWithUnknownExtensionsand set the dword to 00000001. Close regedit and reboot your machine then you can use search to find a word or phrase in all files.