My PC wont come on is it psu or motherboard ?

I finally got the bios screen up last night after upluging all leads and everything i could see but it was only lasting for 15 seconds then it would shut down, I Finally realised that i hadn't clamped the heatsink and fan back onto the cpu so i did this and it stayed on.I then one by one reconnected each device reset the jumpers on the bios and booted the pc after doing this and rebooting the pc about 8 times the pc was back up running.I used it for a couple of hours last night and it was fine,used it again this evening it was fine for half an hour then it froze while browsing and i couldn't do a thing except turn it off at the plug, and when I tried rebooting back came the blank black screen fans running drives running but nothing else,
please help

Ps I'm currently using the monitor so it cant be that !

Matt
August 2007

mabe checking the moniter by swaping it out for another one if u have a spare one in the house
after that do u have any devices like i pods or usb sticks pluged into the pc while it tryes 2 boot up
sometimes this can cuase the system 2 hang (that is if u have usb legacey enabled in bios)so un-plug all but moniter keyboard and mouse
after trying all of the above i,d then try reseting the bios
still no luck after that then u left with swaping out the agp card with one that u kno works
these are the most likey cause,s of a black screen

blankachips comptiaA+ O/S Network
August 2007

couple suggestions to try.
change graphics card, it may have failed, it looks like pc trying to post but no graphics output,
listen for beep code when turning pc on,depending on bios make different beep codes, though usually 1 long beep means no graphics output.
try to reset bios, this is controlled by a jumper that is found near battery. pin 1 2 normal 2 3 reset bios, another trick remove multipin plug from board that carries power from psu to board. then replace.
good luck.

bob macdonald
August 2007

thanks for replying t
The pc is quite old it got a intel d845wn motherboard with a pentium 4 1.5 ghz chip, 2 x 128mb ram pc133 and 1 x 256 ram , Dvd Rom drive sony crx320ee , floppy drive 80gb hard drive and a 30 gb hard drive , graphics card is radeon 7000 64mb ddr and a usb 2.0 card 400w psu and runs on xp sp2.
Dont know much else about it I've checked the voltages on the psu leads to the drives and im getting 12v and 6v
thanks for any help

matthew
August 2007

To check the power supply get a circuit (The outputs should be standard on all/most of the PSUs.) and look for the POWER GOOD line.

It's difficult to help further as you don't really give enough information about your PC.

t
August 2007