# Solved: Computer Turns Itself On When Plugged In



## cgheilman

I do the tech work for a small family business and they have a Dell Dimension 4600 (2.4Ghz, 2.5GB RAM, 80GB HD) that recently developed a problem.

I was told that every time the person plugs the power into the computer, it starts up automatically. As I'm told, he doesn't have to turn on the power button on the front of the CPU, it just starts up and runs normally.

The only recent changes I made to the computer was installing a new backup program (Macrium Reflect) and I recently installed 2GB (2x1GB) of RAM. Does anyone have any initial ideas on what the problem may be?

Thanks!


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## Alex Ethridge

Set the BIOS to defaults and see if anything changes.

The 'power state after power failure' settings may be causing a problem. Yes, I know, there wasn't a power failure; but, it won't cost anything to try that.


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## DerekC

Just out of morbid curiosity, does the user unplug his desktop often??


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## cgheilman

Yes, the computer gets shut off every evening and turned on most weekdays. Would that cause a difference?


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## DerekC

I was just wondering since your original post said it turns on when he "plugs" it in, I was just confused why he/she would need to "unplug" it.


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## Alex Ethridge

> Turns Itself On When Plugged In


I guess I missed that. Does the user go through the normal shutdown procedure AND allow the computer to totally shut down BEFORE unplugging it?

I, too, am curious why it is being unplugged.

FYI: Most BIOSes have a setting for what to do after a power failure--stay off, turn on, resume last state. If the user is unplugging the unit before a total legal and proper shutdown, then that might explain why it turns on 'when plugged in'. Disconnecting before completely shut down is detected by the BIOS as a power failure.

Also, killing power to a running system can cause file table corruption, corrupt files, a destroyed operating system, even in rare cases a total loss of everything on the disk.


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## DerekC

Although, If you mean the computer turns on by its self after it's been turned off (so he unplugs it to keep it from powering on), then it might be "auto awake" settings in the bios, I've seen some bios' have "auto-power on" settings so that signals from network cards or peripherals can power the computer up.


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## Alex Ethridge

Also, look for a setting that has something to do with "Alarm". That term is sometimes used to refer to a setting that turns the computer on at a certain time each day.


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## Rich-M

That's more than likely a sign of a bad power supply.


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## dustyjay

If turni9ng it off then shutting down the Surge Protector is what was meant, And I haven't seen an answer from the original poster, I would go with the Resume Power scheme in bios.


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## cgheilman

The computer is always properly shut down and unplugged from the wall at the end of the day. Whenever he plugs the computer in, the computer starts itself up automatically.

If this turns out to be a bad power supply, is it harmful to run the computer with this problem?


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## dustyjay

I would first check in the bios, to see if it is set to start when power is resumed, this is for power outages but it does the same thing when you unplug the computer and plug it back in. And yes if it is a bad power supply it should be replaced as a power supply can take out the motherboard, processor, ram, video, hard drives, everything it is plugged into when it blows.


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## cgheilman

Alright. I'll check the BIOS first, but it looks like this particular model has a terrible history with power supplies going bad.

How do I figure out what type of power supply I'd need to buy?


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## cgheilman

It turns out the CMOS battery went out and that probably reset the BIOS so the computer itself was set to turn on by itself when it was plugged in. With a new CMOS battery and a quick setting change the computer is ready to go.


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