Crash on joining server; no actual error message

Alright, so me and my friends regular on an RP server. We went there a lot, no problems on the server or anything, until yesterday. I tried joining them in the game, but as soon as it hit the end of the loading bar, I got the dreaded “The program has stopped working properly and needs to close.” (or something similar) and it either closes itself or only gives me the option to close it. Before that, I could connect to the server fine, but I can no longer connect to it without crashing.

I wasn’t given any actual information about the crash in the dialogue.

The specs that I think are important to the situation:
Windows 7 RC (Build 7100)
nVidia GeForce 9600GT
Pentium 4 3ghz
3gb ram