Originally posted by AugeVonBlau:

I've just run into the same issue, if not worse. i just upgraded my gpu to a 16gb. ran skyrim special edition on ultra high quality as the test. ran fine for hours. then I try and play Valhiem and it crashes my whole computer right before it hits the start screen. I've tested a couple games now. Seems like Valheim is the only one doing this. No mods, and i've uninstalled and reinstalled twice. perhaps a windows 11 conflict, or a radeon driver conflict? idk.

It could be a power supply issue. Valheim maxes out the GPU on the start screen, and it could be that your GPU is trying to pull too much power from the PSU than it can handle.