Hi
My computer does this
1 press switch at plug to on, lights flash on the keyboard
2 Press power on switch on tower
3 Computer starts up for about three seconds
4 Turns itself off
5 pressing power button now does nothing
6 press switch at wall to off
7 Go back to one
I have tried a new power supply unit and this made no difference

I have also noted that if i keep reset pressed whilt i press the power on button the computer runs for around ten seconds before it turns itself off

Any suggestions?

Stu

You might wanna try the following.
Only connect the mb,cpu,cooler,minimal RAM & vga. So no HD or cd-rom or other pci cards.

Try resetting your CMOS

If you still have it then, (IMO) i think its the motherbord that shortcircuits something.

Greets Crazy,

Did you change any connectors to the mobo recently, like Power, Reset, Speaker etc.? Maybe one of those is wrong

some motherboards have overheating protection, there should be a jumper on the motherboard to disable that just make sure your heatsink is connected right and the fan is spinning b4 u do. also sometimes you have to plug the cpu fan into the cpu fan plug 1 on the mobo otherwise it will not start. you can usually bypass that by holding down the insert key when you hit the powerswitch. then if all that doesn't help take the mobo, power supply and switch and set it on the table to rule out the possibility of a short to the case. if all that doesn't work start replacing parts till u find out what it is...

I have had same problem in the past and changed the cmos battery, it cured it.

Can you go into cmos and how long will it stay on while in cmos ?

It could be a setting in your BIOS or one of those temperture overheating features. Power supply might be an issue but it doesn't sound like that.

Does "computer starts up" mean you actually see something on screen or is it just the LEDs coming alight?

computer turns off first time works second

I am having a similar but SLIGHTLY DIFFERENT problem-- my home built worked fine for about a month.
Now when I try to turn it on, it turns off after leds light up and fans go, in about 2-3 seconds (never boots). Then a few seonds later (~5-10) I turn it on and it works fine, boots up and works great. Restarts and the rest work fine...

specs:
300 gb maxtor hd
intel mob d925xecv2
msi nx6800 video card
case supplied power supply (rosewill -rated 400w)
printer connected and on
scanner was connected (disconneted to test that)
altec lansing subwoofer/speakers
latest BIOS
windows xp

ps. printer is on different pwoer strip but both pwoer strips into same outlet
(so can't be phase issue)

Any ideas??? for ex, what is best way to test if power supply putting out 400w (without buying another

all the best
Clks