I just got UT3 yesterday and installed fine an everything, joined my first multiplayer game without any problems. My second though crashed during the loading screen, it crashes to the desktop which has changed to super low resolution and like 4bit colour. I only had that problem once last night but today I cannot join a game, it happens every time.

I'm running Athlon X2 5200
2gb DDR2
8800gts 640mb