I get what you mean. This is only in Internet Explorer, right? Or is this in other programs too?
Sounds like IE is screwed up. I forget what version of windows you're running...erm...or version of IE. Please repost that and I'll tell you how to do a repair. Alternately, if you don't have 6.0, you can download it and hope it fixes the problem.
If the issue is happening everywhere (including outside of IE) then you've got windows issues. I'd do some spyware/adware searches, virus scan, etc. If it's this, though, the only thing that'll probably save you is a reinstall of Windows.