my suggestion....System restore to the date a day befor eoyu noticed something wrong. If not, you probably have a spyware thing that had modified your IE by adding to the system registry. Its usually a .dll file that has to be unregistered before you can delete it. My suggestion is to go to http://pestpatrol.com/
and do their free computer scan. Although it doesnt fix your computer, it can track anything wierd in your computer. In my opinion, pest patrol is a lot better then Adaware cause it was able to find 16 spywares that adaware couldnt.
If you do find some spywares using the free scan, use KaZaA or some other P2P software and get pestpatrol. Although its a comercial product, theres no CD key or anyhitng, so you can just download it from someone. Just remeber to scan the file you dload before you run it. And also dont forget to update the program first.