Processor: Intel Core 2 Duo E6750 2.66GHz or AMD Athlon II X2 245e.
Operating System: Windows XP, Windows Vista or Windows 7.
CPU: 2.4 GHZ single core processor.
Sound Card: DirectX 9, 10, 11 compatible.
Graphics: NVidia GeForce 6800 or ATI Radeon X1600 at least, GeForce GTS 240 and Radeon HD 3870 recommended.
going by that, you're at the bare minimum to play the game. It's quite possible that snow effect is too much for your computer to render.