You could try one of the things Squally suggested:

Boot into Safe Mode (don't worry about internet acces or whatever ), and run the System Restore. It should be in the Start Menu somewhere (I can't remember off the top of my head ). Try to select a date before when you installed IE6 but as close as possible to that time, and hopefully the computer will restore itself to exactly (near enough) what it was at that date and time you chose

Of course, this is assuming you haven't disabled System Restore somewhere, but most people don't do that (<I>I'm</I> not most people )