Hi, for some odd reason I'm having trouble running half life 2 and half life 2 lost coast. I start the game up from steam and it goes to the normal loading screen but then it says at the top left "64 bit mode active." Now I don't know what this means, but after it says that it freezes up and refuses to do anything, and I know this because I've left the game on over night and the next morning the screen was still the same. Other than that Half life 2 deathmatch and Counterstrike source both work just fine. Please help me, I do not know what to do. Here is my system:
Windows Vista Home premium
AMD Phenom 8400 triple-core processor
4 GB RAM
Nvidia GeForce 8200