My uncle who is an electrician changed the whole internal electricity system not long ago in my house, but it may be something to do with it, besides, a couple of months ago, there was a black out in my city and I forgot to unplug the cables from the power socket, perhaps when the light returned it may have caused something to the psu or another part of the computer. My PSU is connected to a extension cord I have used for a year or two, but the strangest thing is that I was using a gigabyte motherboard with the same PSU and never had that problem. Since I ran the tests with the multi meter I haven't had any errors so far. I have been thinking to buy a UPS also. I think I'll do that.
Any recommendations for UPS? I have seen only APC brand in Chile
Dude, this is likely related.
Check GROUND!
Also, check polarity (shouldn't matter much, but..)
Here's what I mean.
First, ground. If the electrical work was done recently, and the ground isn't good...that can cause things to be a little unstable on a precision power supply.
It's not that bad, but....could be the problem.
The other, polarity. You don't often think of AC power having a polarity, but there's a reason plugs have a wide blade and a thin blade.
Long story stopped....just find a way to plug the AC power cord into the wall UPSIDE DOWN.
Just to see if your symptoms change.
Rather than test ground (if you don't have a ground detector),....MAKE one.
Tie a wire to a COLD water pipe.
That's ground.
Tie the other end to a ground on your computer.
Power up...try things.
Ask if you need more, I tend to go on
....and right now I'm out the door.