PC locks up / restarts many times per day

Note that I am a user, not a tech.

This has been going on for several weeks.  I took it in for repair and it passed all diagnostics (Micro Center's work notes state that they ran "OCCT" for 1 hour, then again for 24 hours).  Of course it's still happening.  I rarely go more than 2 - 3 hours without a crash.

Today I started taking screen snips of the event viewer after rebooting. I hope someone can look at them and point me in the right direction. Thanks!