When I start the game, it keeps crashing.. It doesn't shut down, but brings me constantly back to desktop, as if I'm alt+tab every 2 seconds.

Check your graphics options for the game from the start menu. If that doesn't work could you please post your system specs and OS?

I use Windows Vista (TM) Home Premium, 32-bit (service Pack 2) with Intel® Core(TM)2 Quad CPU Q6600 @ 2.40 GHz and... I think I have a memory of 3 Gigabyte RAM?

Do you know what graphics card you have?

Crikes, I thought I mentioned that, even after double checking the post:

It's ehh... NVIDIA Geforce 8800 GT, I think; not sure if this is the precise one.

To make it simpler, My model is Acer Aspire M5640-1M7C, this way you'll know the exact specifics of my computer, I suppose.