Check in one of the other threads where you've posted this question -- I've already answered it, as has at least one other person in a different one... (SLOW DOWN - go back and read where you've already posted. You've posted this, what, 5 or 6 other times!! If you can't remember 'em all -- use the "my forums" link)
In the meanwhile, have you checked
this thread? Have you done a
Virus Scan? There are viruses out there that can kill your IE!!!
Here's a link to a free online spyware scanner - it'll automatically download and run.
If you want help, you're gonna have to provide us some more clues. If you get to using HiJackThis as indicated in Schadenfroh's thread (above)
you're going to want to get help! It's a great tool, but it's also a great way to really screw up your computer if done unsupervised!!! PM me when you're to that stage and I can help you.