It's never worked right since Microsoft introduced that feature back in Windows95. It's unreliable at best, and if you really want to search for files like that, I'd suggest installing a program such as Google Desktop. Generally though, it's just better to keep your files organized in such a way that you can find what you're looking for without the need for searching.
Very often when I do a search for a file, it doesn't seem to matter how I do it, but none of the files are found. It searches for a second or less and come up NO RESULTS. I have had this trouble for ages. I know the files are there, but want to know where, many times. I can't believe I'm stranded with such a simple problem, especially I'm not a novice.
Help - please!