crashing to restart every time :(

[SethLive! 0]

Every time I start up arma I crash to restart after about 20 seconds. sometimes (rarely) it lasts for 15 minutes or so but then crashes to restart again. I have reinstalled arma, tried both 1.06 and 1.08, and updated my drivers. nothing works.

Help?

my system specs are: Pentuim 4 3GHz, 2gigs corsair ram, Nvidia 6600 (PCI-e 256mb vram)