Meh, Firewall sucks, it is currently off.
Are u sure? For example u can have 2 firewalls: 1 software and 1 hardware.
The software one is something like ZoneAlarm or Windows-Easy-Firewall. The hardware firewall could be from u router and e.g. if i want to turn him off, there is written with big words: "dont do that! Or bla bla " ;o.
So when i have problems with games, i have to open some ports [TCP/UDP?, etc.]. in the hardware firewall. To change something in this firewall, i have to put 192.168.1.1 into my web browser, login and change what i want
. So look for some guides for ur firewall
if u have it ofc. ^