arma in a window help

[intox 0]

i started arma in window mode by adding -window and resizeing it

but after about 10 mins my whole computer just restarts and thens starts back up.

this does not happen in full screen mode at all just when im playing mp for about 10 mins

i have update gfx drivers and everything

My System

Intel Core 2 duo 2.2ghz

2gb ram

Ati Raedon X1600xt 512mb

500gb hard drive

Thanks Intox