You have done the same mistake that I did with FF. I downloaded FF from a Google pack site. That means that the browser is integrated with the google toolbar. Uninstall google toolbar from this browser and it makes FF virtually unusable. FF downloaded from a Mozilla site is ok. Personally I would uninstall pronto but I can't advise if you would loose any data or not.
Try running a reg cleaner. Ccleaner has one click here . Also run the windows cleaner. Used this prog for a while now and found no issues with it. Then reboot. Have gone off Google toolbar and most of it's other programs with the exception of it's search engine. Still even that will spy on you. Another excellent program to run is cleanup click here .
I prefer Firefox browser over IE7 and think having another browser is good practice...just incase your current browser becomes corrupt or any problems with it. I think you will find most nowadays have at least two browsers on there systems.Firefox2 click here