Random reboots while playing Just Cause

Hi everyone!

I've a new PC (see system specs for details), clean W7 install, all the updates installed. I have installed Just Cause and imported old saves. The game runs great, but then the PC reboots. Minidump is not created for some reasons, and Event Viewer doesn't show any errors before the reboot. Last time GPU temperature was about 60 C when the PC rebooted, and there is no indication of CPU overheating (had this more than once with my old Pentium IV@3.2). PSU also seems sufficient, besides reboots happen after some time in game.

Any suggestions where to look for more information? I don't have much experience with W7.

Thank you for yor reply, my settings were "write minidump". Chandged them to "kernel dump". I'll write about the results.

The memory is not created even with "Kernel memory dump" set. I don't see BSOD, perhaps the PC is rebooted even before the OS has a chance to write a dump?
On the other hand, NFS:Carbon looks pretty stable, i.e. no reboots.
In a few days I'll try to install Win2k3 (x32), may be that'll help for this particular game (Just Cause).