Windows 10: Computer crashing shortly after startup

As the title says, I have a new computer that is crashing almost every time I turn it on. It usually happens in the first few minutes after start up and usually only happens once. If I start any gaming, or even try to watch you tube, I either get a black screen and restart or at times a blue screen saying my pc has ran into problems and needs to restart. My daughter also has regular crashing playing Fortnite with her friends but the computer does not restart completely in these cases.

:)

 

Can't get GPU-Z to start with Windows 8.1 startup

I'm not sure how to do that. Could you list the steps for a noob?

 

Computer freezing/crashing shortly after startup

A couple of days ago my PC randomly froze during normal use and required a hard reboot. Ever since then it has been freezing or crashing about 1-3 minutes after startup. Everything functions completely normally up to the point of the freeze/crash. This happens during regular use, on the login screen, in the blue Windows recovery screen, safe mode, clean boot, sometimes even during the startup while the Gigabyte logo is still displaying. The only place where it does not happen is in the BIOS menu, which I have left on for several hours without a freeze or crash, so I don't think it's a Mobo issue. I've had this PC for about 2 years now. I've tried a laundry list of things and haven't been able to figure out the problem yet. Didn't install any new software or anything in the weeks prior to this occurring.

List anything you've done in attempt to diagnose or fix the problem.

Windows Defender/Malwarebytes checks (all fine)

Safe Mode (crashes)

Clean Boot/all processes disabled

Reverted most recent Windows updates

Reinstalled Windows 10 (Got a DPC Watchdog violation error at first, now just back to the crashes)

Tried to upgrade to Windows 11 (can't finish update before crash)

Flashed BIOS to most recent version

Updated all drivers

Checked RAM and SSD health (both okay)

Checked all connections in PC are secure

Monitored usage/temps (no spikes right before crashes/freezes)

Also had a tech support rebuild the master boot record which they said was corrupted but still having issue.

Minidump file: minidump

 

all games crash!

I suggest you run rthdribl > http://www.daionet.gr.jp/~masa/archives/rthdribl_1_2.zip
Increase the window size step by step and watch your vga temps permanently.
What happens?
If it crashes, run at stock speeds as suggested before and retry.

P.S.: When your system locks, does the display signal turn off after a time?
Stuttering sound or no sound at all when freezing?
What X1800XT model do you own exactly?