On to the next step, then.
Empty the browser's cache and dump all the temp files. If that doesn't fix things, the next thing is spyware...always a suspect when IE starts acting squirrely.
If you haven't already, download, install,
immediately update and then run
Spybot and/or
Ad-Aware. Read the help files to familiarize yourself with how they work. I recommend you use them both since each tends to find things the other misses. Let them clean up any spyware found.