IE 8 won't display ANY web page?

Using XP SP3 on a Dell xps 400.
:confused
I made the huge mistake of trying IE 8.0. Will not display ANY page.
I am using an old ATT Yahoo browser for this session.
Get this message on every page: "A malfunctioning or malicious add-on has caused Internet Explorer to close this webpage".
However, I am running IE 8 without add-on's.
When I first installed IE 8 it worked fine. But the next day it would not display web pages.
I uninstalled and downloaded again. Same result.

Any help is appreciated.