It's been going on and off for awhile. A few weeks ago I stripped the whole system down and built it outside the case and cleaned everything out then today it's having the same problems again.
Played Div2 for about 3 hours last night without a issue but turning it on this morning it refused to boot then the random reboots started
Well since replugging those cables sorted it for a bit I'd assume they are dirty or even check your power supply