I also have the same problem as reported in other threads here. Somthing stops access to web pages but leaves email and non www pings unaffected. I've only just tracked the probelem down to the Web Shield. Terminating the Web shield allows pages to load again, but if I try to restart it, I get a message " The provider is waiting for a subsystem to st.." the rest of the message is under the AVAST logo.
When the web pages get blocked it leaves iexplore or firefox processes still running and they cannot be terminated, I end up having to turn off the power to shut the computer down. Not ideal.
I have an Acer Aspire 5920, running Vista home preimum service pack 2, Zone alarm free firewall, Microsoft Defender and AVAST Free version.
Has anybody got a solution to this problem, as I don't really want to change AV programs, but I can't keep crashing my computer to shut down.