System crashes, Event ID 41

Hi everyone, I'm trying to help a friend troubleshoot his computer but haven't had much luck so far so figured it best to consult your expertise! He's had random crashes/reboots, and the Event Viewer log shows a repeated pattern of the following non-Informational entries:

Error, Source = EventLog, Event ID = 6008, "The previous system shutdown... was unexpected."

Critical, Source = Kernel-Power, Event ID = 41, "The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.", BugcheckCode = 0

What troubleshooting steps would you recommend? Are there any additional logs I should post that would help?

Thanks!