[AChimp]

Does this always happen, or only when you visit certain websites?

What's happening is that the original IE process started running a script that opens a new copy of IE over and over and over and over. It's one of those things that's designed to crash your computer eventually.

You might have some kind of spyware installed, or you visited a website that had a script like that on it. A good example is the link in Number Guy's signature (or what used to be... too lazy to check).