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An old computer that has been working perfectly for three years has started to behave strangely after it had been reassembled in a new case. Now it always restarts in 4 seconds after shutdown, no matter was it turned off with the power button or programmatically, by the OS means.

I would like to get rid of such a behavior, but I have no idea about its reason, and how can I cure it.

I have unplugged all devices and add-on cards, taken the motherboard off the case, disconnected the front panel wires, cleared CMOS and changed the battery, tested the MB with three different PSUs, even tried disconnecting the keyboard and the mouse -- the behavior does not change. Now it's just a bare motherboard connected to the power supply that lies on a table -- and it still goes on in 4 sec. after it had been turned off. Holding the power button pressed (or power switch pins closed) for 10 -- 12 sec prevents it from going back on. All the BIOS settings pertaining to power management are disabled (AC back -- Always off, Power On by keyboard and -- disabled, etc.) The CPU and the RAM are the same that were used before, I have not even uninstalled them.

It definitely has no bearing on the OS, as this behavior remains the same without even HDD/SSD connected and after resetting CMOS.

The hardware is:

  • mobo: Gigabyte GA-H61M-DS2 rev 2.0, BIOS F4 (12/21/2011),
  • CPU Intel Core i3-2130, 3400 MHz,
  • RAM Kingston KVR1333D3N9/4G x 2, 1330 MHz
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  • How can a "bare motherboard" boot or shutdown, and boot to what?
    – harrymc
    Sep 13, 2017 at 8:49
  • @harrymc, I did not say it boots, it just turns on -- fans spin, and it allows to enter BIOS setup (if the keyboard is connected). It can be turned on/off by closing the power button pins, even without the case and without power button connected to it.
    – m. vokhm
    Sep 13, 2017 at 10:02
  • Do you mean that this "bare motherboard" reboots itself after 4 seconds?
    – harrymc
    Sep 13, 2017 at 10:17
  • What OS are you running on?
    – antzshrek
    Sep 13, 2017 at 10:29
  • 1
    I have the same problem on an aged PC (2009): of you press the power button once when the PC is booting (before the OS is starting), it shuts down (no fan, all leds are off), then after 4 seconds, the PC power up on its own. But when the power button is pressed for 5 seconds instead of just once, the PC shutdowns and does not power up again on its own. This behavior started to occur after the BIOS lost the date and time. I confirm this has nothing to do with the OS. I tried to disconnect all devices and disable all ”wake up" BIOS settings without success. Sep 3, 2022 at 21:57

3 Answers 3

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Press Windows Key + R and type in regedit and hit enter. Locate the following key:

Location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

Double Click on PowerdownAfterShutdown

Then, Change it to "0" if it is "1"

OR

Change it to "1" if it is "0".

And hit Enter.

Then restart the computer and after it restarts try to shutdown again. Hopefully this will work for you.

But if this doesn't work make sure you change the value in regedit back to what it was originally

Then You try this:

ErP Ready mode must be enabled under the APM Configuration in the BIOS.

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  • As I said before, this issue has no relation to OS or its settings. The behavior remains the same when the CMOS was cleared an no OS was booted after it. The ErP changes nothing.
    – m. vokhm
    Sep 13, 2017 at 13:07
  • My PowerdownAfterShutdown was "0", set it to "1". It seams to work, no more auto restart after shutdown! Thank you! Before it I also tried disabling the fast startup at Power Options with no effect.
    – Pedro77
    Nov 3, 2017 at 10:55
  • No, it is still restarting. Intermittent problem
    – Pedro77
    Nov 5, 2017 at 14:24
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Inspired by https://superuser.com/a/923477/269608, I disconnected the power cable, then removed the CR2032 3V battery for 30 seconds and replaced it, then plugged the power cable again and restarted the PC.

I had to reconfigure the boot order and the date/time, but my PC now shutdowns as expected and does not wake up on its own.

[Edit] This trick worked only 2-3 days, then I had to replace the CR2032 3V battery with a new one. Now everything works as expected.

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  • Quite probably that in my case the old battery (and spoiled BIOS settings) was the reason too. The computer had been lying unused for a couple of years before the whole story began. Perhaps changing the battery and/or resetting the BIOS the way you described would solve the problem. Now I don't remember, perhaps I did so
    – m. vokhm
    Sep 5, 2022 at 19:05
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Due to some mysterious reason, after installing all the required software (FAR, Eclipse, Notepad++ etc) everything has started to work properly. What was the reason of such misbehavior and why has it suddenly disappeared -- I don't know. I don't like this sort of mystery but I can do nothing about it.

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