IE 6 Stops Responding

Hello, I upgraded from IE 5.5 SP1 to IE 6 Sp1 on Windows 2000 SP4. Now, for some reason, some websites appear and some do not load at all, stops responding. I did not change any security settings at the beginning. Then I lowered all the security settings and the same issue was found.

Any ideas why this would be happening, very frustrating.
Thanks.