Hi cactusjack,
Just upgraded to Comodo version 3.0 while the original Comodo version was still there (Win XP Home),
did not detect any upgrade problems. The trick here is that Comodo version 3 is much more strict and for some programs you have to allow install status else it alerts for every one and all dll's that are being changed during the process. As the firewall is set properly the absence of alerts is a comfort to the user. View active connections is a very welcome feature. I had a monitor program to do that that I had adopted to my personal likings using Resource Hacker, still use that to get a view of all my undergoing connections and save the logs for later inspection, like "Open Time, Close Time, Remote Address, Remote Hostname, Remote Port, Network Interface, Local Port, Service Type".
The only program that gave me some adjustments to make were the updates for Ad-Aware 2007, might to have to reinstall that to fit my new Comodo settings.
That's it basically,
polonus