There seem to be a lot of potential causes for this. One suggestion I've read/heard is to go to Control Panel->Add/Remove Programs->Internet Explorer 6.0, and double click. In the box that comes up there should be a repair choice. Select repair and let it do its thing. I'm not real hopeful in this case since you have reinstalled it, but you never know. If I had to guess I would say something is going on either at the network interface, or IE is encountering a problem setting up/reading its cache folders.