I'm !@#$%^&*uming that you had read and tried everything in the pinned topics at the top of this forum. You could also check out http://beginners.subspace.net which has a good amount of well written FAQ and Troubleshooting docs. If you really wanted to test it, you could try hooking up another PC on that network under the same router as your PC, then try playing the same zone (in spec of course, make sure this is ok with your favorite zone's staff.) If they both lag at the same time, then its a network problem, not a PC prob. If only your machine lags, then there is something causing it. To go more in depth requires more info, so I will leave it at that for now. The basic rule of troubleshooting something like this is a ON/OFF thing. Use ctrl-alt-del to view all the apps running, and close anything you don't absolutely need. Trial and error to figure out what it would be.