firewall problems..again..

[coldish]

Ive looked through the boards for help but im not hugely computer competitant so I thought it best to get some proper advice. The problem is limewire appears to be finding a firewall however what this firewall is I have no idea. I have tried turning of windows firewall plus I have CA antui-virus which I dont actually think has a firewall so I am stumped. More confusing is the fact that it was working friday, I have touched nothing and when I tried to connect today it wouldnt work. I am using windows xp and my internet provider is orange wireless broadband. i cant remember what other system requirements I need to give. please someone help?