you said the problem appeared close to installing Comodo 3. Have you tried completely removing it just to exclude it from the problem?
It happened before. But generally it was due to Gmail ips being blocked by PeerGuardian.
Some boots and things get back to normal.
After installing Comodo, I got it work once I suppose... nothing more.
I'm afraid to uninstall Comodo as it gave me a lot of work to get it working...
Did you make any changes to the Windows Mail or STunnel configuraton?
No.
Is the k9filter involved in the proxy chaining for your Windows Mail?
It shouldn't. Only on http traffic. It was working all the time, both on Vista and XP.
Which ports do you have the Internet Mail provider set up to intercept?
110,11110,120
The spamihilator at 120 is disabled and not being used.
The last set of questions are just because I was wondering if you might have accidentally set avast scanning into a loop.
Ask as much as you need to help me. Thanks.