1. Recently I came home from a trip and my computer was on! I am 100% sure I turned it off when I left, so this was the first indicator of a problem
2. The past day, my computer has been randomly turning off. When I restart it the power seems to fluctuate (along with my cold cathode lights) and the computer may not even start up. I finally got it to start up once, but then it turned itself off.
The specs are listed in my signiture. The power supply is a Hiper 580watt Type-R. I had restart problems a few months back, but it went away and I thought nothing of it at the time.
Any ideas if this is a motherboard or power supply problem?
Yeah, try running the PSU by itself. Tell us the results of that. As for that electrical buzzing noise, where is that coming from? The PSU or the motherboard? (Mobo's can make noises too....when their broken....)
The PSU runs fine by itself it seems. I also noticed that when the computer does turn off, the PSU fan continues to spin as usual to rid of excess heat (good sign).
However, today I got the computer to start and heard a buzzing noise near the motherboard. Now when the computer shuts down, it won't start when I press the power button. I have to turn off the PSU toggle switch, then turn it back on. Then the computer will start.
Also, today I pulled out a usb plug out the back of the computer while it was trying to start up and it shut the computer down.
These signs lead me to believe it might be a motherboard problem?
Yeah. Sure sounds like a mobo problem. I would RMA it.
Before you do this, however, remove the mobo from the case and make sure that nothing metal in the case is touching the solder points on the back of the mobo. Make sure that you don't have a loose screw or something hiding back there. This could be the cause of your problem. (but I kind of doubt it however)
The fact that you have to use the psu toggle switch tells me that something is shorting or malfunctioning in some way, and that its likely not the PSU.
What PSU? If it came with the case it may be rubbish! Can you not borrow a GOOD PSU from a friend? It may have been the PSU all the time. If you have to cycle the switch at the rear to power back on, the PSU has tripped on an overload.