New Computer Build, Acting Strange

[ability]

I'm building a new computer and have all the parts installed correctly, but the computer randomly turns on and off.

Parts:
CPU: intel i7 2600k
CPU Cooler: Corsair H70
MOBO: msi p67a-gd65(b3)
RAM: 16GB G. Skill Ripjaws DDR3 1600
GPU: evga gtx 580
PSU: Corsair AX850


I'm concerned because the computer can really only be "shut down" by me unplugging it from the wall. At times, I can turn it off, but it will randomly restart. I once turned it off, unplugged a USB mouse and it turned on.

Any suggestions?

I do receive one long beep and three short ones as an error code, meaning the ram is bad. Would this cause the computer to act like this?

I've tried setting the RAM one at a time, and all give me the same code. I'm doubting whether it's the RAM, why would all 4 be bad? Could it be the motherboard?

 

[ability]

I unplugged everything except my power supply/monitor and the error code is now one long beep, two short beeps.

why would this change?

There are several beeps, but my computer starts as normal?

On recent MSI boards, (and those from other manufacturers using AMIBIOS) as well as a single loud beep to indicate successful POST, you'll also hear some lower tone beeps. This is just the BIOS notifying you of USB devices connected as it looks for bootable USB devices, and input devices such as keyboards and mice. The number of beeps will change depending on how many USB devices you have connected. If you see the POST screen / BIOS logo and your system boots as normal, then you do not have a problem!

This is from this forum post : http://forum-en.msi.com/index.php?topic=129806.0 : would the two short beeps indicate the two USB connectors I have plugged in on my motherboard?

This still doesn't explain why I have random reboots, hangs, and random "on" occurrences.

I haven't attempted to install windows yet.

 

[mfenn]

Any USB "chirps" would be as the result of USB devices plugged in, not just headers (those are just extra lengths of wire really).

As for your main problem, given that the symptoms apparently changed after unplugging peripherals, I would suspect that you have something installed incorrectly. Try pulling the mobo out of the case and doing a minimal boot with just the CPU, 1 stick of RAM, the GPU, and power cables plugged into the mobo.