PC randomly restarts out of nowhere

cross-posted from: https://sh.itjust.works/post/60545062

As title suggests.Coming home the other day I find my PC started to restart out of nowhere, with no warning before or errors afterwards. I haven't changed anything and haven't had this problem before.

Any suggestions on what to do?

Device specs:Processor Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz 3.60 GHzInstalled RAM 64.0 GBStorage 233 GB HDD ST9250315AS, 112 GB SSD OCZ-VERTEX2, 466 GB SSD Samsung SSD 970 EVO Plus 500GBGraphics Card NVIDIA GeForce RTX 3060 (12 GB)System Type 64-bit operating system, x64-based processorOS Windows 10