In startup and recovery options (system properties), set your computer to capture a kernel dump and tell it not to reboot after a crash.
Get a copy of the minidump and PM me for my email addy. I can run the minidump through a debugger and at least tell you what was at the top of the stack when the crash happened. This may or may not indicate the culprit.
Save the kernel dump file (memory.dmp) for someone with better debugging skills (dclive does these as a hobby, try reaching him).
Get every driver on your system updated. This means video, chipset, sound, SATA, you name it. Update system bios.