hmm I had some sort of problem like this one... somewhere I had picked up a toolbar, which was blocking all search pages, crashed IE and more stuff... (just like you said) spybotSD couldn't find it, but you gan get information from the searchbar about the makers site, and he had a removal program. that didnt remove it, but somehow did kill it, and then I could simply uninstall it via the "install/uninstall software" button in the config menu. hope that fixes it.
(btw, if you dont use the remove program, the bar keeps comming back.)

~Alex