Power issue diagnosis help

Hello,

I went to load up resident evil 2 and my pc just black screened and turned off. It then attempted to turn itself back on which it did for about 3 seconds , and then it switched back off again. Since this incident a few hours ago I cannot get it to turn back on.

I’ve made sure all connections are correct from the psu and elsewhere, i’ve done a power reset (unplugged all usb connections and held it off for 30 seconds) My guess is the psu went bang as it has black screened before when running on high power intensity , but it has never not turned back on

Specs: Nvidia gtx 1080 intel i7-8700k 32gb ram all corsair (2x8gb 1x16gb) 700w builder psu msi a370 mobo 512gb sata ssd 2tb hdd sata

Another thing , I recently changed pc case and motherboard so maybe the increase in fans and bigger motherboard was too much power , it doesn’t seem like an overheating issue either. I can build a pc just about but i’m not a wizz at these things so any help can be appreciated.