pc stopped working

[unclecrash]

HI all, i have a problem with my daughters pc.
Siemans desktop pc. On starting it immediately and continuously powers off and on. other than the sound of the processor fan turning on and off there is no other obvious activity. The monitor does not come out of standby. The f1 - f12 functions have no effect. The on/off switch has no effect. Power can only be shut of using the switch mounted at rear where power supply is inserted. There was no obvious time at which this happened, just went to turn it on and problem was there.

Your views much appreciated.

[GoNz0]

power supply ?

do you have a donor PC to try spares from ?
open the case and take out the cmos battery you see on the motherboard, test it to see if its flat or less than 3 volts, change it if thats the case. while the battery is out unplug from the mains and press power on to clear the CMOS (unless your happy looking for the CMOS reset near the battery)
otherwise strip out what you can so your left with power supply, processor and memory connected, see if it starts beeping at you, if it does add the video card back (unless its built in) and try again. if it still works and you have bits left over, keep adding back 1 at a time till it acts up again. bin the part that causes the fault and buy a new part

hope thats of some help.

(and make sure its turned off while your adding and removing )

[unclecrash]

Okay i will try the cmos battery in a mo.

I stripped out (in this order)the hard drive, cdrom, video card and modem one at a time. There is no floppy. All that was left was the power supply connected to the motherboard. On starting exactly the same as described in first post happened.
I took out the ram and on starting i got the beeping you would expect.

I replaced each item one by one starting with the ram and then reverse order of extraction on the others and each time i started up again i got the same result continuous off and on as stated previously.

Like i said i will try the cmos suggestion.

Thanks for your reply.

[GoNz0]

might be bad ram if it beeped at that stage, you got 2 stick that fit ? a spare in another PC ?

as you stated, motherboard & CPU caused a no memory beep, and as soon as the ram was in it power cycled. rule that out if the bios reset doesnt do anything.

[unclecrash]

okay going at it now and i let you know.

Thanks again

[unclecrash]

Okay i have no access to a multimeter at mo so i completed procedure as you said and replaced battery from other pc. No luck still same

[GoNz0]

ok, any news on swapping out the ram ?

[unclecrash]

No the ram on the other computer is different just checking if i can pop up road to mates pc and check on that.

[unclecrash]

Hi again. I cannot swap the ram. The other computers available have different sockets. Does that leave me fairly stuck or can i presume for a start that new ram is needed

[GoNz0]

well to be honest its a good path to follow, you could always pop the ram to the local pc shop and ask em to test it based on you buying a new stick if they come back as faulty

shouldnt take em more than 5 mins to test it for you, if it works slip em a fiver for there trouble and consider getting the rest tested.

[unclecrash]

Cheers Gonzo.