Windows XP Search Puzzler

Hello,
The XP searches I do are pretty much always to find something on an external drive. I always start by going to My Computer, selecting the drive, selecting the folder and clicking Search from the menu bar to bring up the search companion. I then enter part of the file name and click Search. I hardly ever use the Advanced Options.

The first search always works perfecly. But if I initiate a second search from that same page by changing the file name, it almost always gives me an immediate negative result.

If I then go to the Advanced Options, I see that in the Type of File box is listed AAC Audio Book.

I don't want to search for a particular type of file, but I can't get back to a blank in the type of file. And the pulldown, although it has dozens of file type listed, has nothing for All Files and Folders.

I have to X out of the search, re-click My Computer and start over.

When I do start over, if I click Advanced Options, the Type of File box is empty, which is what I want. I just don't know how to re-empty it after every search..

I do a lot of searches and it's a pain in the butt to have to close the search every time..

Anybody know how to fix this minor, but annoying problem? I can find nothing online about it. The AAC Audio Book file type is the first type listed. I just don't know why it defaults to that after almost every search. Other XP PCs have (All Files and Folders) listed as the first type in the Type of File pulldown. This one doesn't.

I gather that it's some sort of registry setting that needs to be changed, but I don't know what the tweak or fix is...