PC turns on by itself and shuts off moments later

whenever i shut down my computer. Some time afterwards it starts up and just ends at a black screen. I don't know if this is due to a overclock or what. I have a seasonic x series power supply and im using an i7 4790k ,

it has to do with the motherboards settings in terms of what it does when it looses power.

If you have it set to automatically turn back on in the event of a power outage , it might be seeing some of it's shutdowns as power outages and turning itself back on automatically.

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Thanks! i will see if i can find that setting to turn off.

Check your BIOS settings to see if it's being powered on by anything.
Also, check your OS settings to see if your machine is actually turned off (Some Win10 settings actually put the machine to sleep)

I have the same CPU and PSU as you. lol

Seasonic X-850 to be exact. My PC did that to me for a while. Actually, it only does it when I turn on my home theater PC. (pushes power button to turn on home theater PC - then a second later, my gaming PC turns on)

But it only does it if I use my wireless keyboard that's hooked up to the HTPC. My gaming PC has no wireless capabilities. Not even WiFi.

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sometimes your machine does a post and powers down, after shutting down unexpectedly, and you try to power it on afterwards.

It's doing a system check. If there's any issues it will output beep codes.

It's common. Especially with OEM systems.


Okay, so it must be either your PSU or your MOBO. Try resetting your bios to defaults. If that doesn't work, try reseating all power connectors. It sounds like it's your motherboard turning on your system unit. I guess your power supply can be inadvertently powering on your system after shutting down. Try putting your PSU in another system... see if it happens. If it doesn't, then it's your MOBO, has to be... especially after resetting bios configuration.

Strange issue, because your system should post and have some sort of video. Since you do when you boot up normally, that tells me it has to be your system board or the power supply.

post edit: check that little switch at the back of the PSU and make sure it's on automatic. Try all three if you have to.

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Maybe the cmos battery is doing funky stuff/with what to do on power loss?

Not long ago I had a similar issue with a computer that would sometimes turn off about 10 seconds after it was switched on. It was an issue with the power switch. Try temporarily swapping over the power and reset switches (they are both the same) and see if the issue persists.


I blame Windows 10. Every other update breaks something (but it does fix something else...damn you, MS)

Some mobos have a dehumidifier function. They will turn on a few time after shutting down to run fans. Supposedly removes moisture. It maybe turned on in your bios/UEFI.

im on 8.1 though!

it's a 200 dollar asus mb i don't think this is that sophisticated lol

would it have anything to do with the 4.8ghz overclock i got going?

same here nothing wireless. You do have a good point ever since i switched wireless mouse's i stopped having that happen but then again i haven't shut my computer down much either. i will report back and maybe this is the fix.