Computer and fans turn on for 1 second then turn off

By Dethklok ·
I've searched through the threads but i am still unsure of what my computers problem is.

the fans and the lights turn on and then turn off right away. I have tried a new motherboard but that didnt work. i tried a new processor but that didnt work. I was wondering if it was because there was not enough thermal paste but the problem still happened when i put a new processor on with new thermal paste.
what else can cause this problem? my pc has been working fine for over a year now and this just happened . havent done any changes to the system.

AMD Phenom 9500 Quad-core
ATI Radeon HD 4850 1GBDDR3
2GB DDR2 Ram
450w Power Supply
300GB Seagate HDD
Windows XP Pro 32-bit Service Pack 3

Thank you very much in advance.

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All Answers

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Did it boot up

by Jacky Howe In reply to Computer and fans turn on ...

with nothing attached. IE: no addon cards no HD no CD/DVD. Have you tried another PSU (Power Supply Unit) as something maybe triggering the over voltage detection.

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check voltage

by SystemCheck In reply to Did it boot up

back of power supply a little red switch make sure its set to 115

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If swapping the switches doesn't work

by Jacky Howe In reply to Did it boot up

First thing to try is loosening the Screws that hold the Motherboard to the Case. They will only need a full turn. Reconnect the Power and turn it on. If it powers up shut it down and retighten the screws. They only need to be firm.

Make sure that there are no loose screws or other components inside the case. These can cause shorts and other serious problems with the PC.

Also check the power outlet that you are connected to by plugging in something else and turning it on.

A faulty (PSU) Power Supply Unit can also cause it. Fluctuating power or an underpowered PSU is not good for the Motherboard. You should be running 500-600 Watts. Try another one if available or replace it.

If it's none of the above try this Bench Test.

Carefully remove everything from the Motherboard. Remove the Motherboard and put it on an anti-static mat on a bench. Check the mounting stands and make sure that they line up with the holes on the Motherboard and they are all of the same height, so they are not shorting out the Motheboard. Remove the Power Supply if it is a known working one to test with. Remove the Heatsink and give it a good clean. Remove the CPU and reseat it. Reinstall the Heatsink remembering to use CPU grease. Reseat the RAM and test with one stick at a time. Connect a hard drive and the Video Card. Connect the Power supply to the Motherboard. You can use a flat blade Screwdriver to short the Power pins on the Motherboard if you haven't got a spare switch. Connect the Monitor and turn it on and see what happens. If it stars up add one Device at a time to test it.

Troubleshooting Flowchart

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looks like you dont have enough power or your PSU Died... i would Upgrade

by Snuffy09 In reply to Computer and fans turn on ...

you have a 450W PSU and your running a quad core and a HD 4850 gfx card...

I have a 4830 gfx card and the min power requirements are a 450W PSU

I also have a high power dual core CPU (but uses a lot less power than your quad core)

I have a 650W PSU

if you built this system yourself get a new more powerful PSU... If somebody else built it for you go smack them in the face for insulting your power needs.

you should have at least a 500-550W psu

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I 2nd this....

by ---TK--- In reply to looks like you dont have ...

I was researching the min requirements for HD 4850 graphic cards, and the min is 450 watts. Which you are meeting. But if you are constantly drawing the MAX that the PS is designed to handle, then you will burn it out pretty quick.

Snuffy is right min. PSU you should go with is 500-550... but if you can find a PSU that is 650 W for the same price as the 550Watt jump for the 650, it will be better for future upgrades...

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Awesome replies

by Dethklok In reply to looks like you dont have ...

I will get another more powerful psu. thanks all. i will repost if the new psu doesnt fix the problem

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Power supply failure

by mjd420nova In reply to Computer and fans turn on ...

As suggested, checking the voltages should give you the clue that the power supply has failed. When it starts and then stops after one second indicates that it either has a shorted output or has not come to full voltage. A miltimeter should confirm whether it's the 12 volt or five volt supply that has failed. Since you've replaced the MOBO and it didn't cure the fault, the power supply is the only other solution.

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okay so now that i know its a power supply failure

by Dethklok In reply to Power supply failure

What would be a good power supply to get?
in terms of wattage. how much would be enough for my pc.
600w? more? less?

thanks in advance

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Try using this PSU Calculator ...

by OldER Mycroft In reply to okay so now that i know i ...

Start from scratch, fill in ALL the details that you can:

Recheck everything you've entered as detail (just in case) then move up to the next available PSU.

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by Jacky Howe In reply to okay so now that i know i ...

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