Maybe one of the add-ons is causing the problem? I'm using IE9 now (FF5 is my default), I think IE8 had this as well. From Control Panel, open Internet Properties, click on the Programs tab. Then Manage add-ons. Try disabling all the add-ons, then start IE8, if that works then start enabling the add-ons one by one. Tedious, but probably the best way to figure out the problem. Btw, have you applied all IE8 updates?