Ok when you said you had uninstalled McAfee did you mean you had got rid of the whole program ??
With McAfee these are the parts you need to uninstall...
http://www.gnutellaforums.com/258193-post45.html
Also you said you Port Forwarded can you give me that exact model number for your modem/router as if it's listed at the PF site I can give you the instructions for limewire...
Did you connect fine with Cox cable on your old comp or have you changed ISPs as well, as Cox are known for shaping p2p...