NotoriousMIC

I'm having two issues. The most annoying is that I can't start a multiplayer game in a LAN because it keeps telling me that the CD key is in use. I bought the game on steam. The second issue is that when ever I load up the game it keeps minimising to desktop, it does this a few times before it starts working. I have tried running it in compatibility mode (I had the same problem with San Andreas and this worked) but that did not work. Anything I can do about this?