I am having problems with the Comodo Firewall in Win7 and the game OpenTTD. If i launch the game online the screen goes black and freezes. I then have to re boot the pc. If i launch the game with out the firewall i have no problems. I also manually made a exception for OpenTTD in the firewall but i still get the blank screen.

You are more than likely getting D+ alerts when in full screen.That will lock up your pc. When you know your pc is free of malware follow A note to gamers so CIS will automatically learn the rules.

Thanks for that information. It is now working.