About a year ago, I shut my desktop down for the evening and the next
morning, the desktop was turned on. Thinking maybe I’d clicked on Standby
instead of shut down. I carefully shut it off that evening. The next morning, I
could hear the fan running and the light on the Power button on the tower was
blinking. That night I shut it off by holding the power button on the tower
until I heard it shut off. It was back on the next morning. Now I’ve lived
alone for the last eight years and have only one house key. I tried reformatting
and reinstalling XP a couple of months ago, but the problem has not changed.
I’ve been unplugging the power cord for about a year, otherwise it will be
running when I wake up without fail. No problems with my laptop. Any
suggestions would be greatly appreciated.
In this excerpt from
Answercast #76, I look at a computer which mysteriously turns itself on each
night. No, it’s not ghosts!
Computer turning itself on
So, there are two things that come to mind.
One is fairly unlikely, but I have to mention it anyway. That is: sometimes there is a protocol for allowing your computer to wake up, or to power on, in response to a particular kind of network message. Now, of course, when you turn off your computer, most computers don’t turn themselves completely off. There’s usually something (even if it’s just to keep time) that keeps running on those machines.
When that option is configured, the network card actually remains somewhat active and it keeps monitoring for this “wake up packet,” if you want to call it that.
It’s rare. It’s really rare that it would happen in a home situation. This is something that’s more commonly used in a corporate or industrial environment. I mention it for completeness because it’s one of those things that, maybe, could be factoring into this.
It’s typically a BIOS setting that you can turn off. So I’d have you look into your BIOS to see if that were the case.
Power switch problems
The more likely problem is the power switch itself of all things.
Many of the power switches that we use are actually… I want to say …not really “hard” switches. They don’t actually switch off the power. They are typically a very small, low voltage switch that then triggers a higher voltage switch that actually deals with the power.
So what you’re actually pushing on is something, typically, that turns out to be fairly cheap. It’s not like the light switch on your wall; it’s more like a keyboard key that instructs the computer to turn the power on or turn the power off.
If that switch is (for whatever reason) kind of, sort of intermittent, then when the computer is running, you’d never notice; because even if that switch were hit just briefly, the only time the computer (when running) is going to respond to that switch, in most cases, is if the switch is held down for a long period of time. That’s not the case with an intermittent switch.
If on the other hand, at night when the computer is turned off, the switch (for whatever reason) decides to maybe “spark” or a little bit of static electricity maybe sets it off; that could be confused by your computer as an instruction to turn itself back on.
Unfortunately, I don’t know of a really great solution for this one.
I mean, the power switches are kind of a pain to replace, if you can even get the parts. My recommendation (in fact, the recommendation that my assistant ran into when he was looking at this question) is to get yourself one of those switched power strips. When you turn your computer off at night, after everything has been turned off, hit the switch on the power strip, too.
That’s the moral equivalent of unplugging the machine like you’ve been doing this entire time. But it is going to remove all of the power from the computer and ensure that it can’t start up no matter what the case.
So those are things that come to mind. Power strip: it’s not an elegant solution, but it’s a practical one and it can certainly last until you get yourself a new computer some day.
(Transcript lightly edited for readability.)
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