Black Ops Lag Suddenly

[#1]

Hi been playing black ops past 2 weeks have Been great despite strict NAT Type no Lag atall, untill tonight played 7 lagged in Every game! unplayable even with UK Host, ive tryed restarting Router but didn't fix it, not got a chance to Test fifa yet, Only thing i can remember doing is
installing firefox on my laptop earlier before i played also Uninstalling rubbish off there... 

[#2]

Were there any other computers on in the house at the time? Sounds like something would have been downloading, or possibly streaming - if that was the first time you'd turned on the laptop in a while it could be that it was downloading windows updates, which would have caused the issues you describe.