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My computer suddenly turns on and off automatically. At first, I think it is because of some software updates that requires restarts. So after it happens many times, I shutdown my computer to see if it is just restarting or shutting down and starting again. Then, it turns on by itself. Then I checked if the shutdown was caused by installed software by going to BIOS screen and waiting for some time. Then, it turns off by itself. After that, I believed that it (both turning on and off) can be caused by any recently installed software since the operating system doesn't boot up yet.

So I think that it is a hardware issue. Maybe something jammed the power button of my computer. But after doing some cleaning inside my system unit, I tested it again. Then it didn't happen again after some time. So I think that it finally solved the issue. Then one day (after 2 days or so), it happened again. After that, I searched if it possible for a software to cause both turn on and off. What I saw surprises me, a BIOS feature can turn the computer on (Resume by Alarm feature). Before that, I don't know that it is possible to turn on a computer without physically pressing the power button (just like other appliances).

But I can't find that feature in my BIOS. Now, I am wondering what causes this issue. It is still happening untill now although not as frequent as before.

My questions are:

  • Is it possible for this issue to be caused by a virus?
  • If it is a hardware issue, do I need to replace a part? What part?

Another thing that makes me think that it is caused by a virus is that there are some services that I allow to run at startup asks me if it can make changes on my hard disk (I am using a standard account).

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  • Unless someone posts an answer indicating that this might actually be a virus, you might be better off asking this question on Stack Overflow (or asking a moderator to move this one), focusing on the "What could be causing this?" question in general, rather than "Is it a virus?".
    – Ray
    Commented Mar 8, 2018 at 23:52
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    @Ray I don't think this would be on topic for Stack Overflow.
    – Anders
    Commented Mar 9, 2018 at 8:42
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    When your computer is unexpectadly shut off, does it go through the ordinary shut down process, or does it just go black?
    – Anders
    Commented Mar 9, 2018 at 8:43
  • @Anders Maybe Super User as jrtapsell suggested, then, unless there's a more hardware-oriented Stack Exchange site. But it should be moved somewhere. It's an interesting problem, and the OP clearly put some solid work into testing things and gathering data before writing the question. They deserve an answer, but the only one they're likely to get here is "It's something other than a virus."
    – Ray
    Commented Mar 9, 2018 at 21:37
  • Is this a tablet, laptop, or desktop tower? Sounds like it might be a desktop/tower, since you said you cleaned inside... if you disconnect the power button (after turning it on or off) does it still turn off/on by itself?
    – Xen2050
    Commented Mar 10, 2018 at 3:14

2 Answers 2

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Could a virus boot a machine?

This is the easiest way to attack the issue, it's unlikely a virus could boot the machine unless it either:

  • Is on another machine on the same network and the machine can be woken over Wake On Lan
  • Persists in the BIOS (very rare)

What hardware can boot the machine

In likely order (IMHO):

  • The power button
    • the button shorting out would cause phantom presses
  • The PSU
    • flakey power + boot on power applied
  • The motherboard
    • could cause the same effects as above
  • Some expansion cards
    • depending on card and BIOS
  • Some external IO devices
    • depending on device and BIOS, for example serial can do this
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  • Even if it persists in the BIOS, I can't imagine how it could boot the machine at will. The most it could do is configure the NIC for Wake On LAN and similar. When the system is powered down, the BIOS is no longer being executed.
    – forest
    Commented Mar 9, 2018 at 2:12
  • Booting the machine at a specific time isn't done by the BIOS, it's done by the Real-Time Clock. It's customary to program the RTC startup timer through the BIOS, but it's quite possible to do it from the operating system instead, so you don't need a BIOS-persisting virus to spontaneously power-on the computer. That said, a hardware fault is far more likely than a virus here.
    – Mark
    Commented Mar 9, 2018 at 21:33
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Check if it is simply a heat problem. Your fan not working well or something related to it. I think that you can see what happend before the power Off in the System Log (Event Log).

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  • 3
    OP is asking about the computer turning itself on spontaneously, not turning itself off. Why would a bad fan cause a powered off computer to suddenly turn itself on?
    – forest
    Commented Mar 9, 2018 at 8:27
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    The title said "Turns on and off" So it could just reboot alone. Maybe I misunderstood..
    – AndoKarim
    Commented Mar 9, 2018 at 8:45
  • From the OP: "Then, it turns on by itself"
    – forest
    Commented Mar 9, 2018 at 8:52
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    @forest The sentence "The computer turns itself off (, and) then turns on again"(=0.5s after turning off) sounds as a restart to me. I am not native speaker though, so the meaning can be shifted. But as far as I know "then" can be used for consecutive actions(one started after another) just as good as unrelated actions (ordering). I understand the question as if the computer sometimes restarts when shutting down.
    – wondra
    Commented Mar 9, 2018 at 9:16
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    Sure, but OP didn't say that he simply rebooted his computer. He said he shut it down. It would be odd to ask "Why does my computer turn back on when I reboot it?", because that's what a reboot does. That's not an anomaly. Turning on spontaneously when not commanded to do so is what concerns OP.
    – forest
    Commented Mar 9, 2018 at 9:21

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