I have had CS for quite some time, and never had any problems. But as of today it said my half life cd key was in use, and wont let me connect to any server. I have restarted my computer several times, and tried connecting to different servers, and I get the same message each time. I have never shared my cd key with anyone, so what's the problem? I thought it might have something to do with valve changing over to steam, but all my friends and classmates can connect just fine. Please help