I have this mysterious problem too. I use Zone Alarm Pro 8 (with all Avast entries given Super rights and Access and Server rights as found in this forum).
I have edited the Avast INI file to include the ZoneAlarmCompatibility and ModifyVistaSocketAutoTuning parameters set to 1.
I've tried using firefox with both the localhost manual proxy setting and direct internet connection setting, but i get the same web access freezing problem.
When the computer has just started up all seems well for maybe 5 mins of surfing (I enabled the setting that shows me what the web server is scanning at the time, so I can see that it's working). Then it just stops and Firefox can no longer access any http url's. When I close down Firefox it disappears off the desktop and task bar, but if I run Task Manager it's still there and End Task refuses to work, as does using pskill.
When it crashes, I go to the Avast Protection Control screen, choose Web Shield and then choose Terminate. The icon goes greyed out, but if I go to the Services console, the "avast! Web Scanner" service stays on "Stopping" until I reboot the computer.
I also have SUPERAntiSpyware installed, but this was installed yesterday and I've been having the Avast Web Scanner problem before that, so I know SAS isn't causing the problem.
I have Yahoo Messenger running and a firefox plugin that checks various mailboxes for new messages ever couple of mins. Some of the URLs that are generated by those things seem fairly long... could the long URLs be a problem with Avast Web Scanner perhaps? (yes, I'm clutching at straws here
)
I've heard really good things about Avast and want to get it working before I recommend it family and friends... sadly for now I daren't do that until I know this issue can be fixed somehow.