The Cohhilition

The oldest parts of my PC is my motherboard and CPU, which are a Asus Sabertooth Z77 and i5-3570k. Sometimes I'm getting "pops" in my speakers and one of my monitors (random which one) will flicker on and off at the same time. Recently a group of USB ports on the back panel started losing power and the peripherals would flicker on and off repeatedly, and I've had to relocate to other ports. Now some of the other ports seem to be failing also. I once noticed that even tho my pc was off, a few random buttons were lit on my Corsair k70, which normally is completely off. But now just today while playing Elite Dangerous my entire PC shut down suddenly without even giving a bluescreen (It has always given a bluescreen before the few times that happened). The temperatures were fine when the shutdown happened. I checked the voltages too and they look fine.
I have a Corsair TX 650w PSU which is also one of the oldest parts.

I've been thinking about getting a new motherboard and cpu, but I would really like to know what is causing these errors before buying new things. I suspect it's either the PSU or Motherboard. Could also be something wrong with the houses electricity?

I have moderate experience with IT and built the computer myself.
I would love some feedback on what you guys think the problem could be. Any help is welcome. Thank you.

I highly doubt it's the house causing any problems. If your PSU is working properly it should regulate any lows and highs.

The problem itself; By the sounds of it your motherboard is failing.
How I came to this conclusion: USB hubs are usually the first ones to go, in the same manner you described. Audio problems would also suggest that. Monitors shouldn't go off like this unless the GPU is powered off or there are no instructions coming from the motherboard.

You could narrow down the problem by using different audio equipment (to make sure it's not the audio), hauling the PC to a different room and using a different socket (to make sure it's not the room's grounding or bad wiring)

Some reading Sabertooth Z77 usb 2.0 stops working - Republic of Gamers - Asus

Did you fix the problem utjan ?

Yes, thanks! I didn't take any chances and simply bought a new motherboard, psu, processor and ram. Just got it all put together this weekend. Got a lot of good advice on the curse tech chat also.

So did you gave your old MB and PSU someone to test it ? Have a nice gaming days utjan

Don't know who could test it for me. I'm throwing out the MB, but keeping the PSU. Thank you.

[QUOTE="utjan, post: 41372, member: 50374"]Don't know who could test it for me. I'm throwing out the MB, but keeping the PSU. Thank you.[/QUOTE]

Well you can use PSU on another PC or give it to friend to test it for few days .For MB test you need experts Do you have somewhere records of bsod ?