Bet you've done this, Drapes, but I'll mention it anyway.
Disable your adaware stuff AND any firewall and see if things improve.
If you're using ZoneAlarm, reset to defaults in Privacy, Main, Mobile Code Control, Custom, Mobile Code Control. That'll disable your JavaScritp Blocking.
And I'd certainly recommend IE6 SP1 eventually but this is unlikely to be a problem with your IE. (IE6 is smaller, faster and more robust.)