When on mission game crashes and computer restarts

[hunsnowboarder]

Hi there Everyone! I just found this game an I am so happy about it! X-com was always my favourite game and I was very excited to find this game. However there seems to be some problems.
I downloaded the latest stable version of the game (2.3.1).
My system info:
Windows version: XP SP 3
CPU: Intel Pentium 4, 3000 Mhz
RAM: 2048 MB
Video card: NVidia GeForce 8500 GT (512 MB) (driver: 6.14.11.6218)

The problem I am experiencing is that when I am on a mission the game crashes and restarts the computer. It always happens only when there I am on a mission with my soldiers. Doesn't happen very often, but let's say out of two missions it happens once. Could somebody help me please as I would like so much to play with this game!

Thank you in advance for your help!

[Muton]

more likely your gfx card
driver update
http://www.nvidia.com/object/winxp-270.61-whql-driver.html
gfx stress test
http://www.ozone3d.net/benchmarks/fur/#download

[hunsnowboarder]

Dear Muton!

Thank you very much for your reply.

I downloaded the driver and installed it, but after I restarted the computer and checked the driver it was the same old one. I do not understand why doesn't it update.