won't boot into bios even after cmos reset

Hello! New here. Just built my first PC for my kid—all brand new parts. Everything rans smoothly; he didn't have any issues for over an hour. I asked if he tried ARK: Survival Evolved yet, so he boots it up, plays for a minute and the computer crashes. Whenever I turn on the PC, the CPU, PSU...

Had this motherboard for well over a year (it is older than that) and was doing fine up until tonight when I rebooted. There was no prior incidents related to motherboard wear that I had noticed: wasn't sluggish or slow to boot, no lock up or phantoms, etc. I used it in a secondary build in the...