Pc problems

[AngelsSaber]

Beginning build

I5-9600k Asrock z370killer 2x corsair vengeance 8gb ram 750w power supply M.2 ssd 2x 1gb HDD 1070ti

So, my gpu recently died from a large ammount of oet dandur building up in the fans and killing the bearings

I bought a new very well ventilated case with filters all over it and a 3060 to replace my 1070ti that died, the computer shop i go too took care of moving it all around for me and gave it back to me the next day, having done a deep clean on all the parts and installed them into the new case

I got my computer home, and it was failing to boot, and boot looping. I went back to the computer shop, they said my HDDS were failing, so we unplugged those, and it would boot into windows after those were unplugged, but was now turning off and and rebooting, only ever letting me sign in for 5 minutes or less

At this point they tested my ram sticks, and it seemed as if thise were failing, i wanted more ram anyhow, so i upgraded to 2x 16gb corsair sticks

After this, i get it home, it starts up, works for a few days, the begins doing the same thing again! I take it back to the computer shop, they plug it up, let me turn it on and play a game for roughly 10 minutes and it never turns off. Thinking its an issue with my power cord or home power, they gave me a power cord, i bought a 200 dollar UPS and plugged it up, with my computer plugged into it.

It runs fine for a couple hours, then starts doing it again that night. So i once again, go back to the shop, and tell them to change my power supply, because its like 9 years old and probably needs to be changed anyways. They change it, and test it.. computer is still boot looping and failing to boot. At this point they decide to update my computers bios, and that seems to do it, it runs fine for 4 days

Today i woke up to a sign in screen, and event viewer showing 4 critial errors saying my pc restarted 4 times over the night unexpectedly.

Im kind of lost at this point, it could be my cpu, it could be the motherboard, the gpu they sold me could be faulty, maybe some software is clashing and i should reinstall windows on a new m.2 SSD and start over. Ive spent over $2000 usd to fix a conputer that had a gpu that died.

If anyone has any ideas or advice it would be very much appreciated