I have a new Vista laptop which I purchased 2 weeks ago, and ever since day one I have had problems.IE keeps freezing and only a forced reboot will get it working again. I have tried Firefox, but exactly the same thing happens. I know there is nothing wrong with my internet connection as I can plug my other XP laptop in and it will run 24/7 without any IE problems, so I think this is something to do with Vista.
I have a Vista PC running Avast and it kept freezing. After doing some research on the web I turned off one of the features in Avast and the problem went away.
Basically Avast was opening too many connections to the interent (to do security checks on web sites) which broke the Vista limit.
If you are running Avast the feature to turn off is WebShield.
I un-installed the new versions of Avast and AVG as they were not particularly compatible with my Vista. I installed Avira Freeware instead and have had no problems with it.