I have been a Comodo user for many happy years up to XP Pro. Unfortunately due to my ignorance, I ran into a problem with using it with my new Windows 7 Ultimate 64Bit.
I first started noticing dropping connections. I would disable and re-enable several times to get back on. The failures all indicated connection to the wrong IP. My troubleshooting went no further than turning it off, after a lingering difficult issue with Zonealarm. As soon as I turned it off, the problems vanished. Not wishing to troubleshoot it I just went to AVG and it worked fine. I had the opportunity to get McAfee Paid version and am using it now.
So this is just a reference for beginner's that they may have problems with Comodo.
The symptoms above seemed all that was wrong.