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Computer starts by itself, when you plug it in.

Msg#: 4377033 posted 12:34 pm on Oct 20, 2011 (gmt 0)


My cousin is having an weird issue with her computer.

So, When you plug in the cable in the power supply, it starts the computer by itself. Not a normal start... Like, only the Coolers and red LED that displays the HDD usage is on constantly.

I have taken everything out ... HDD, Optic drive.
I only left the power supply cable that powers the motherboard in, with the CPU one out. And plugged the cable in the wall socket. It starts by itself. I have even taken ll the little wires out that manage the power/reset button, and the two leds for hdd processing, and the green that indicates its working. Same issue.. it starts by itself.

I have taken a power supply that i had around, and tested it on that computer.

I can see a green LED, which is placed on the mother board on, but i cannot start the computer. I even tried to make the contacts for the power button with the screw driver, but the computer wont start at all with my power supply.

I am totally LOST. I cant figure it out what it could have.
Could anyone Please find the time to read my topic and give an opinion?

Thanks in advance,



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Msg#: 4377033 posted 12:42 pm on Oct 20, 2011 (gmt 0)

I think there are settings for autostarting in the BIOS. Boot it up, go into the bios settings and have a look around.


Msg#: 4377033 posted 12:47 pm on Oct 20, 2011 (gmt 0)

The computer wont start at all.
After you plug it, It starts the Coolers etc. But the Computer doesnt Start. So i cannot enter Bios. It starts but doesnt sent any video signal.


Msg#: 4377033 posted 1:50 pm on Oct 20, 2011 (gmt 0)

Sorry for the double posting.

Okay, so i've been there again, i eliminated all parts, cpu, graphic card,RAM, motherboard battery..... Left only motherboard and power supply. And then i powered the PC. Again.. the power supply started all by itself, with the motherboard green led powered.. I cant explain myself why wont it even beep after i took the RAM out.

Can it be that the motherboard got broken?
I dont see anything wrong on it.


WebmasterWorld Senior Member 5+ Year Member

Msg#: 4377033 posted 2:33 pm on Oct 20, 2011 (gmt 0)

well if you only have a mother board sitting there without even a processor.... its not going to beep or do anything.

the computer auto starting right when you plug in the cable isn't exactly a werid issue, it happens to me all the time, seems to be a random occurrence i just flip the switch on the PS turn it off flip it back then its business as usual.

but if it ONLY does that every single time you plug the power in i'd be looking at the PS or the MB.


Msg#: 4377033 posted 6:25 pm on Oct 20, 2011 (gmt 0)

I meant it doesn't beep even when you get the RAM out.
I think it should beep if theres no RAM, but i havent tried that in a long time so im not sure.

I used the switcher too. When i switch it ON it just starts..
But it starts only the functions.... lik coolers etc, wont give any signal.

I think the issue is motherboard related. As it controls the power button etc.


WebmasterWorld Senior Member 10+ Year Member

Msg#: 4377033 posted 6:29 pm on Oct 20, 2011 (gmt 0)

Check the front power button and a reset button if fitted. Sometimes they get stuck pushed in.

That's a gotcha from the past 20 years.


WebmasterWorld Senior Member 5+ Year Member

Msg#: 4377033 posted 6:50 pm on Oct 20, 2011 (gmt 0)

you are correct it should beep if you have no ram........ BUT if your PC speaker isn't hooked up :-)

reset button stuck haha yea thats a gotchya.

will the motherboard power down the system if you hold the power button?

also what kinda system are we dealing with?

its not always the motherboard just because of the power issue.

a motherboard with a bad proc will respond to start up and shut down commands, but nothing will happen, no video, no beep, no screen.

a motherboard with no proc installed will only shut down via pulling the plug from the power supply.


Msg#: 4377033 posted 7:24 am on Oct 21, 2011 (gmt 0)

Frank, i have specified that the computer starts with only the MB and PS. The buttons etc arent connected.

I have explained well enough above but i will try again.

If the power supply is powering up the motherboard, AND ONLY THE MB ! Nothing else, no RAM, no video, no cpu, no wires for powering or reseting it, The PS Starts by itself.


WebmasterWorld Senior Member 10+ Year Member

Msg#: 4377033 posted 11:16 am on Oct 21, 2011 (gmt 0)

Sorry did not read the text where you said you had disconnected the switch headers.

So you are not getting any POST. No beeps, even with the RAM and GFX out.

Keep the CPU in.
Make sure the CPU fan is plugged in and working
Make sure you have plugged in the CPU 4 pin power connector (if one required)

Now power up that. It should give fault code beeps.

If not do you have an onboard speaker? If not make sure the case speaker is plugged in to the correct header.

Best if you state the model of motherboard. Can then check if it's supposed to beep if no CPU installed.


WebmasterWorld Senior Member 5+ Year Member

Msg#: 4377033 posted 3:31 pm on Oct 21, 2011 (gmt 0)

no header switches and it still powers up!?

i'd pull the 4 pin power, the motherboard power and anything else its hooked up to. If it powers up just sitting there alone not hooked up to anything in the universe that PS is smoked.

do you happen to have a mulit meter to read voltages?


Msg#: 4377033 posted 6:17 am on Oct 22, 2011 (gmt 0)

I have said already, The 4 pin power wire is out when it does this.

If i have only the motherboard and the Power supply Cable that powers the MB, ONLY. both start by themselfs.

I think the MB is messed up, as i already tried to use an other PS, And it wouldnt listen for the buttons to start (wouldnt start by itself with that)


WebmasterWorld Senior Member 10+ Year Member

Msg#: 4377033 posted 9:46 am on Oct 22, 2011 (gmt 0)

A few crossed wires here I think.

You need to state the motherboard. Haven't got a clue what 4 pin power plug you have pulled. It could be the front switch header, the CPU power, the side piece on the 20/24 pin main socket, a GFX 4 pin, a hard drive 4 pin ....

And I don't exactly know what the problem is here. You seem to state that 'the motherboard powers up on its own'.

Why is that a problem?


Msg#: 4377033 posted 10:35 am on Oct 23, 2011 (gmt 0)

Man, i have tried the PC with or without the 4 pin cable 4 the cpu. Same thing. The problems that it powers everything.. but doesnt display anything on the screen.

I have wrote everything very detailed in my opinion :|


WebmasterWorld Senior Member 10+ Year Member

Msg#: 4377033 posted 6:35 pm on Oct 23, 2011 (gmt 0)

And I think we tried to help you but you did not answer our questions.

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