I don't know if it was Windows or my hardware, but my PC just shut down and restarted randomly. I thought I heard a sound of some sort, what could be the problem?

Edit: I've attached my status to see if you guys can find anything wrong.

Hiccup from the power supply, maybe?

There could be a lot of problems causing this. My one Laptop is doing the same and I know it is a problem with the Hardware (not 100% is it is the hard disk or RAM.

Which Windows Version are you running? If you are running Vista or Windows 7 and when you sign in as an administrator, Windows should tell you some stuff about the reboot.

I don't know, it just says Windows didn't shut down properly. It did it again just now.

At this point windows should ask you to report to microsoft about that problem, if I'm not totally wrong, you can see what is reported to them (even without sending the info), this should give a few clues on the main problem.

I'm not sure it's asking me to do so. Could it be a problem with parts touching metal or something and shorting out?

here's my PSU http://www.corsair.com/en/power-supply-units/hx-series-power-supply-units/hx-series-hx750-power-supply-750-watt-80-plus-gold-certified-modular-psu.html

Could it be Malware?
It's doing it a bit more frequently, this is bad...

I'm running Windows 7 64-bit, but i'm not getting a prompt to sign in (I may not have mine setup to do that) nor am I getting a report.

I'm on my old PC right now as i'm afraid of the new one getting damaged from the restarts.
Could the cause be that slight damage on the back of the motherboard around the screw holes for mounting the standoffs? The PC has been working fine up to this point despite that. I don't what to do, but i'm in total fucking panic mode right now as the new PC wasn't cheap. Please help.

I had a similar thing a while ago (blue screens, random restarts, beeps, occasional failure to start Windows) and it turned out to be due to a faulty motherboard. It was the last thing I checked, too, since memory tests said the memory was faulty, hard drive checks crashed, etc. It was still under warranty, and I got a new one.

Could be a lot of things, though.

I doubt Gigabyte or Amazon is going to replace the motherboard with that scratch on the back.

Here's the scratch in question. http://imageshack.us/photo/my-images/259/mbdamage.jpg/

I've seen some suggestions about going into safe mode and such, what should I do?

I really don't think the scratch is the issue. But this definitely sounds weird. You could always try booting up a live CD of Linux Mint or something like that, to rule out software as the cause. If it's hardware, well, it could be a lot of things. The thing to do in that case is remove components one by one, but with everything being integrated these days, that's pretty hard.

Make sure there is no possibility of accidental metal-on-metal contact in the case, that would be the first thing to check.

Here's the motherboard in question: http://www.newegg.com/Product/Product.aspx?Item=N82E16813128545

I can't really see anything in that picture of yours. Try holding the camera a little further away and zooming in if necessary. Use a tripod if you happen to have one. Taking good closeup photos can be pretty tricky with a point&shoot camera, an even harder with a phone.

I'll have to do that tomorrow as it's pretty late, but everyone please keep an eye on this thread cause i'm gonna need your help.
Sorry, my camera is a bit finicky. The scratch should be right beside the standoff. You may see a little gray metal looking scratch near it.