a newly build pc keeps restarting when i try to play games. On some games it instantaneously restarts when i try to play them like The First Descendants. Others it'll let me play awhile and then crash (e.g Cyberpunk 2077)

As far as i know its always been like this. But sometimes it'll just fix itself and stop happening like Helldivers 2. i can now play that game as normal. Im at my wits end before i have to send it in for a repair. Its watercooled so its probably going to be very expensive. I've noticed stutters before it crashes. Any help would be appreciated.

My power supply is a hx1500 and i checked that the connectors were secure twice now. My SSD is a Crucial T705. it also doesnt seem to be a overheating thing atleast not for the CPU and GPU. I'll check again to make sure tho but in the meantime what can cause this.

EDIT: it crashed on cyberpunk and showed a code OD and did not restart until i manually powered it off. i also noticed intermediate stutters before it crashed

EDIT: Noticed it stutters constantly in BIOS. will try updating BIOS again and see if it changes.