So have just bought borderlands through steam and whenever i've tried to connect to play Co-op it keeps saying unable to login due to no online account. ( yes i do have a gamespy account )

First i've checked all my firewall/av's settings to make sure it's allowed ( even turned them off and tried to no prevail ), Was then told that borderlands required certain ports open on your Router to be able to host/join games. So followed way of doing it and still no prevail cannot connect to login.

Can anyone confirm a way to check to see if your ports are open? or if possible tell me how i can open the ports up for sure? Just so i can rule out that the ports are open and it's actually a game thing rather then a Router issue! ( sagem 2504fast, guessing. Black one )

Any help would be greatly appreciated! been trying for last 2 days to sort it!!