PC Turning on/off Repeatedly

almost sounds like a power issue. I would see if you can test with another power supply.

Failing that, pop out your video card and try to boot with the onboard video. This will reduce power consumption and may get you into the bios.

see if the on power loss settings is soft off or last state or on. This is a bios setting with power management on most boards.

If it is on or last state, maybe the power supply is folding(powering down) then when the load is gone it tried to fire up again(so the system tries to power up again) and fails.

If this still fails, you should try another power supply. Power supplies have a Power OK lead so if they do not think they are working right, the power supply can tell the board. Not all boards listen to it, but most new ones should.

Have you flashed the latest BIOS for that board? Some people having problems with it on Ivy apparently.

Yes, it has current BIOS.

I've tried disconnected and unplugging the video card, as well as trying a single stick of ram and even no ram in the slots and it does the same thing. It's not even on long enough for me to get into BIOS to see anything, it literally goes on for a second at most and then right back off and just loops this.

I'm stuck in a hard place here because I don't know if I should order a new mobo to test out or a new PSU. I don't have access to one anytime in the near future to test with other than buying one.

depending on how much money you can spend on this, i would probably get a new PSU first. what is your current PSU, can it run your system? you said it was a new build. perhaps your PSU has been working to hard.

You need to bug some friends, someone has to have a power supply you can test with  

It's a Seasonic X Series 850W

Everything was working fine, I go out of the room for about an hour come back and it's doing this. I don't get it at all.

It does it even when it's sitting on a piece of cardboard with no components plugged in. I guess I'll just order a new PSU.

Even the best power supplies can have a failure.

You may want to try to hotwire the power supply, but you will want to ONLY do this with some fans or other devices(old hard drive you don't care about) and not be connected to all your hardware.

This is done by shorting the green wire in the 24 pin connector to any black. You should have some kind of load as some power supplies do not start right with no load.

http://www.techarp.com/showarticle.aspx?artno=268

Remember not to add the wire/paperclip or what ever to the power supply with it plugged in. before disconnecting it, unplug in and hit the power switch on the tower to remove any left over power in the psu.

Note: some power supplies will not work with this, this it is not quite fool proof, but may give you an idea.

I just had this exact same problem two days ago. I did many searches online and found many different explanations which sucks because it means you have to do alot of troubleshooting. Before you buy anyhting like a new PSU make sure your fan hasn't come loose from the CPU. It sounds silly but that turned out to be what was causing the issue for me. I pulled my entire system apart (minus the CPU and fan) and put back together and left components out such as graphics card to test and see if a piece of harware was causing it. Finally I noticed was that the fan had come loose and I don't think the copper heatsink on the fan was coming in contact with the processor. I think the mohterboard must have recognized the processor was getting too hot too quickly or somehting and prevented it from strating. I think the only reason it kept restarting after preventing startup in the firstplace was that PME Event Wake Up was enabled and so the LAN kept turning it back on. First check your bios settings to see if you have something similar which is turning the system back on. Then check that the fan hasn't been jarred loose. This may not be what's causing it but it's a pretty simple check that won't take long. Never hurts to eliminate problems. If it has come loose you might check it while your at it to see if you need new thermal grease.

Best of luck to you if this doesn't help you

-REG

**edit @ SinisterMessial below: I'm sorry it didn't help. I was using my computer before it happened to me as well with no temperature problems either. I'm not sure how it worked itself loose in the first place and it's possible it was unrelated to the constant restart issue. All I know is everything worked after I reseated the fan. I'll be interested to see what you find out the problem is for you. Unfortunately, judging from what nukemaster is saying it sounds like the PSU. I hope that doesn't mean mine is on it's way out... And again good luck!

I shorted the green/black wires and started it with one fan connected, and it powered on and the fan started spinning. Not sure what this means :|

Thanks for the suggestion RareElusive, I double checked the heatsink/fan setup and all seems to be secure. I was using the PC right before this happened and it was on when this happened getting fine temps so I'm not sure it's related to something like that.

it is just a basic test that some use to see if a power supply is at least starting, but with such a low load, its not quite ideal. I if you have a multimeter you can see what the voltages look like

black to yellow is 12
black to red is 5
black to orange is 3.3

Okay, I have a multimeter and I'm going to test these.

Before I start, there is also 1 purple, 1 gray, and one blue wire, What should these read out as?

Also, should I test the ATX CPU cable as well? Should I expect the same voltages?

All the voltages are fine. I double checked the CPU pins to make sure none were bent, and they are fine too.

It's literally on for a split second before it turns off again and repeats over and over, not even long enough for the debug LED to come on and display something. I think it has to be the board.

Could still be a power supply issue. If the load of bringing a full system up may cause it to shut down.

It is a shame you do not have another system to test it in.

The other colors

Purple is a 5 volt(standby) that is on ALL the time. It allows lets say usb ports to be powered when the system is off.

Grey is a Power Good signal. I am not 100% sure what the voltage should be. I did have an Antec(EA430) that stopped working because the power ok voltage was wrong, but I just RMA'd the thing never had a problem since.

5 volts as per Wikipedia  
http://en.wikipedia.org/wiki/Power_Good_Signal

Blue is -12 volts(yeah its a negative voltage   ).