Chosen Solution
Recently my PS3 would run a game normally and while playing the system would shut off completely there is no blinking lights nor is the red standby light on. I can unplug it and it won’t come back on and the light may come back on after a few hours. The time when the system shuts off is intermittent but once it does it stays Down for hours as if it was unplugged all together.
Probly overheating. Need to open it and clean out the dust and replace the thermo pasted should fix it.
Could also be the hard drive maybe doing it. Or could be the power supply.. You would need a muti meter to check the power supplyl for the hard drive you can try going to the secret menu and trying option 2 and 3 to see if that helps. Really without seeing it. Justed kinda guessing.