Same problem
I have the same problem, my computer is restarting randomly, once every few days, usually in the middle of the nite, when I'm sleeping, and I wake up the next morning finding my computer to have restarted by itself. I found some minidump and followed the instructions mentioned above to debug them.
Windbg said the culprit is mostly ntoskrnl.exe, but also vsdatant.sys, ndis.sys, and netbt.sys. I know vsdatant.sys is from Zone Alarm, but I don't know about netbt.sys and ndis.sys. I tried to Google it but can't find anything useful.
Do I have to uninstall Zone Alarm? It's working perfectly, although quite annoying with its constant warning.
Thx.