Start search stopped working

Start search was working fine, but at some point it just stopped. I'm
not sure if it was when I installed google desktop, but I reset my
defaults, and set the search protocol to explorer, and that didn't
help.

What is happening is that I type in the start search notepad (or
whatever) and where it previoulsy would have come up with notepad
after a few letters, it now simply clears the start menu and says 'no
items match your search.

Any suggestions?