Question PC suddenly turned off and won't come back on

[HCMKULTRA]

I was playing a game in fullscreen mode when all of a sudden my PC completely turned off. At first I tried simply turning it back on but then it wouldn't display anything and the mouse and keyboard (both are USB) won't connect either. I removed the plates, turned it on, and took a closer look and it seems none of the fans are spinning, the red lighting keeps flickering, and a sound keeps coming from near the fans and it infinitely loops. I tried using canned air on the fans and it seems to have done nothing. I also tried reconnecting the display cables and it's not working either. Any suggestions or tips?

 

[Aeacus]

Full system specs, including PSU make and model (or part number) is? Also, how old the PSU is, and was the PSU bought new or used/refurbished?