"Old"?!? 30 years? I have clothes that are older than that.
Yeah, my house is 60 years old, had many two-prong outlets
when I moved in, and even had some aluminum wiring mixed with copper.
But i had been living here like 11 years and i didnt have problems with my electrical instalation before.
That does not mean it cannot go bad or deteriorate. Outlets can wear out, wire connections in outlets and service panels can become loose, or even hungry rodent or insect damage can occur. One of those AC outlet checkers can still show if the two remaining wires are still wired properly.
Even so, many two wired outlets can still provide a ground if metal conduit was used. You just use an inexpensive adapter like
this and attach that green loop to the center screw of the outlet cover plate (I am sure there are similar adapters for your type outlet). This is
NOT ideal and certainly no guarantee it will provide a ground. But it might. A good ground is first and foremost, safer. But it will also help reduce or eliminate "noise" and/or interference which can also affect power supply performance.
If he connected a hdd to a sata port he hasn't used before, it is possible that port is sending too much electiricity
Sorry, but that makes no sense. Ports don't "send" electricity. Connected components demand and pull what they need. So the only way "too much electricity" could go through that port is if that drive was faulty, had a "short" (abnormally low or no resistance) in a circuit somewhere, and was demanding too much current. But that, of course, has nothing to do with when the port was last used.
It also makes no sense that disabling the ASUS surge feature would cause a game to freeze.
I would swap in a known good PSU and see what happens. I keep several on hand but for those who don't, finding a trusting friend or relative who will let you swap in their PSU would be a good idea before spending money on a new PSU. IMO, we have not ruled out a failing graphics card or even the motherboard yet. I would hate for you to spend good money on a new PSU only to find out the problem remains. However, since EVERYTHING inside your computer depends on good, clean, reliable power, you still need to verify you are supplying that.
So I am afraid you are stuck between a rock and hard place. Welcome to the world of electronics troubleshooting.