CSS, L4D, TF2, and all of my other SDK-based games haven't worked properly for at least a month now. Valve support was zero help, so I'm trying this board out.

I can open up the game, look through the server list and even see who's in the server, but when I try to connect, it gives me a generic error message. "Connection timed out after 4 retries."

I've tried DMZ, forwarding all ports, turning off my firewall and any other program that would interfere, uninstalling steam and my games completely (twice), and even switching operating systems. The thing that pisses me off is the fact that my brothers' pc, sitting 5 feet away from me, on the same router, runs the games perfectly fine. So it's not a network issue, it's something wrong with my pc. I've tried everything I can honestly think of. Hopefully this thread will bring up a fresh idea.