My first guess would be that you have a spyware infestation. IE attracts that stuff like a moth to a flame.

Download a copy of AdAware, Spybot, etc and run them a couple of times. They'll probably come up with some stuff you can delete.

Then do yourself a favor and get a copy of Mozilla ( http://www.mozilla.org ) and start using it in place of IE and OE. It will help reduce the risk of being infested with spyware all over again. Not to mention shield you against most email worms. You'll also probably come to love the adaptive junk mail filter of Mozilla's email client. The more you use it, the better it gets at detecting spam messages and whisking them off to a junk folder.

You should then do yourself a second favor and get another 256MB of RAM minimum. I did some freelance work cleaning off people's systems... Some of those HP systems with only 256MB of RAM would take about 45 minutes compared to 10-15 for everyone else. I think Best Buy has a rebate deal on 256MB sticks this week, so it might be a good time to buy.