[EMERGENCY] Game won't load any maps :(

I bought the game today, installed it but I can not play. The game crashes every time I load a map. It gets to: Loading: 100%, then crashes.
System specs:
Win7 64 bit
AMD Athlon 630 II. Processor
Nvidia 9800 GT GPU
3 GB RAM ( Note: I'm getting another 8 gigs for Christmas, will it run then?)
I have been playing the 4..0.x version, it was not bought, I admit (please don't ban me for that, I have it bought now!!!) and it ran fine with texture quality on med and everything else on low. I had...

[EMERGENCY] Game won't load any maps