I just want someone to confirm this before I go online and buy the part (which is probably going to be expensive).

Just took a look at my cousin's Acer (ASUS) Pundit computer. It's one of those small form factor machines. Well, I pushed the power button and the power lights up for one second and shuts off immediately. I popped the little critter open and watched the fan spin for one second and then stop. I have to unplug the cable and replug it back in, in order to push the power again to see if turn on for one second...nothing.

My first guess was power supply...then I used one of my power supply testers on that 20 pin (I think) power cable and the fan started to spin...no problem there This is my first time using a power supply tester, but I assume that means it's definitely NOT the power supply.

So right now, I'm guessing is has to be the motherboard right? Like I said, I want to make sure this is the correct piece to get since it will probably be expensive since this machine is not that old (about a year only). Not sure how I can test out a motherboard to be sure it's not faulty (like using power supply tester for power supply testing), so if anyone has ideas on how to do this, I'm all ears If it helps, the ethernet port is lighted up when the power cord is plugged in...but I don't think that means anything. Board probably still bad?

Thanks.

I HAVE THE ANSWER!!!!!
PC Fan Spins For One Second And Stops - No Bootup

I found this thread when I had the same problem last night. Just moved my computer to a new tower case.
(Monolith)
Same exact problem. Tried a new bios battery. Nothing.
The same thing was happening on 2 good power supplies.

Led/fans kick on for a split second, then total shutoff.

Took my motherboard out of the case because it was working that morning in my stock HP tower. Held it in the air by the heatsink and plugged the 24 pin power and 4 pin power into it and nothing else.

Vuala! cpu fan starts and stays on. After going through the process of elimination I realized THE MOTHERBOARD WAS SHORTING ON THE METAL CASE.
If you haven't resolved it yet, try putting a non conductive foam or plastic between the case and your motherboard. I believe they sell them at electronics stores. Good luck!

-reply by ryan

Maybe it has something to do with your bios or there is something wrong with your drivers. If all else fails just do system restore, if that doesn't do, format your computer and reinstall windows. But that'll take a lot of time...

We have had quite a-lot of wild guesses, some from people blaming the OS before the disk has even had time to spin up, lol....

anyways, after testing the PSU, i would agree that its probably a BIOS issue. My first computer suffered exact same symtoms (which diesnt necceserily prove that its the same problem)

Unfortunatly for you... its usually easyer to replace the whole motherboard than it is to get a new bios chip, and then get that new bios chip flashed with the correct bios firmware.

but with new motherboards as cheap as £15, who cares.

Power Shuts Off after a second or two after computer boots, fan spins then turns off.PC Fan Spins For One Second And Stops - No Bootup

Ive had the problem you are all experiencing before. Before you worry about changing anything else, reseat your RAM. I did this and it fixed the problem. If not ram then most likely CPU. More than likely its not the PSU due to the fact that it is starting up. Your computer goes through a series of checks upon startup and if one of your components arent working it will shut off completely. The first component that does anything is your BIOS chip. It takes information that is stored in your CMOS battery and it tells all your other components how to function. (clockrate etc. You can change these in BIOS.) from there you check your CPU (processor). Your processor communicates with a chipset called the Northbridge which in turn communicates with your RAM and your video card. It also communicates with your southbridge which in turn communicates with every I/O (input/output) device on your system. It could also be your motherboard. One of the most annoying issues to troubleshoot in my opinion.

-reply by Hewitt

fan spin for 2seconds and stop PC Fan Spins For One Second And Stops - No Bootup

my pc wont start up the fan spin for 2seconds and stop after I have change the power supplier still or is it the processor faulty coz before the was a sound coming from the inside

-reply by sipho