PC not booting

Richard M · 30 Apr 2008 at 16:20

Hope someone can help out with this.
Basically when I push the power button everything will turn on for about 1 second and then turn itself off.

I have done the following:

Cleaned out the inside to remove dust with a soft brush
Reset CMOS twice (by removing battery for 20 mins and also by the jumpers)
Replaced the PSU with a better one
Taken out graphics card, RAM, unplugged all disks

None of this has made any difference and it's still doing the same thing.
I just push the power switch, the fans spin for a second and the LEDs on the front panel come on and then it just switches off.
With the graphics card in, the monitor also turns on for a second but then goes back into standby when the PC turns itself off.

Any ideas?
It was working fine last night and I shut it down in the normal way from Windows.

Richard M · 30 Apr 2008 at 18:07

I've done this and I also took the motherboard off the tray and screwed it back in to check that nothing was touching the back.
Still getting the same thing - turns on for 1 sec and then turns off again.
It did turn on a few mins ago but I had no RAM or graphics card in, can't figure out why it would do this.

Richard M · 30 Apr 2008 at 18:10

Ok I've solved it!
Now this gives another problem - when I hold in the reset switch with a screwdriver it will turn on but how can I disable the switch or whatever? Or how can I get it to stay held down?
I know about the jumpers that fit onto the motherboard - is there anything I can do here?

I use one of those (old?) Lian Li aluminium cases than have a big power switch with the smaller reset switch underneath.
Underneath this there are the power and HD lights.

Richard M · 30 Apr 2008 at 19:06

Hmm ok it turns on now, but the monitor doesn't turn on and I'm getting repeating long low beeps from the BIOS speaker.
My motherboard is an MSI NForce 4 which uses the Award BIOS.
According to this site it says it's a RAM issue but I've tried with both ram sticks in every slot by themselves and no good so far.
http://www.msicomputer.com/support/sup_tshoot.asp#1_4

Richard M · 30 Apr 2008 at 19:51

Just noticed something else as well - the different PSU I put in uses a 20 pin connector but the motherboard has a 24 pin one.
It seems to work fine and power up because all the fans run and the computer is putting beep codes out.
Will using a 24 pin PSU or 20>24 pin adaptor likely fix the problem of it not posting?