Normally when we use the search companion on Windows XP to find all files that containing specific text, we may end up with not being able to find our files.
This is because we have to enable the index files with unknown extensions option of the Indexing Service. But we do not need to enable the Indexing Service itself.
http://weblogs.asp.net/bkcarroll/archive/2004/09/09/227355.aspx