PC switches on and off by itself

  talia 21:06 24 Jun 2003

My friends PC has started to switch itself on and off.
It never gets to boot up before it switches off again.
We have replaced power unit and disconnected each drive in order, taken out cards one by one but the problem still persists.

Any ideas???

It is a HP machine running XP and is three years old

  Kermie 21:21 24 Jun 2003

What is your set-up?

Athlon etc?

Doies your M/B have the cpu anti-fry thingy on it?

  Umbra 21:29 24 Jun 2003

I can't remember where you find this but.....

There is a setting somewhere "Wake on LAN" which means that the PC is started if a network connection is started. This will occur if your modem is plugged into your phone line and someone dials into your phone line.....this tells the PC to start up ready to receive network / internet messages via the modem.

This happened to me for a while, and after discounting ghostly messages I found this option somewhere to "Wake on LAN" and I unticked it. No more problems since then.

I apologise for not being able to find just where this setting is, could be modem, network or BIOS setting.

Anyone else with ideas???


  talia 20:02 25 Jun 2003


It has a Pentium 3 and what doe the 'Anti fry' look like.

I do not think it has it anyway.

have just tried a different hard drive but no joy

  keith-236785 20:34 25 Jun 2003

TRY the reset button, see if it is stuck, you could try remove the wires from the motherboard to determine if that is the problem.

unplug the case reset connector block from the motherboard (rst sw) or something similar.

try booting up again

hope it works, if it does then you may have to remove the front panel and check the reset switch.

  woodchip 20:46 25 Jun 2003

Pull the plug I bet it cannot put that back in. Seriously though it sounds like a driver problem

  talia 21:13 25 Jun 2003

Have taken reset out and same thing happens.

have disconnected each drive seperately and it still does not more than a few seconds.

I am beginning to think that there is a problem with m/board itself

  sil_ver 23:02 25 Jun 2003

Have you checked that all the fans, especially the cpu heatsink, are running, make sure that the heatsink is making good contact with the cpu die. Check that all your cards are seated (take them out and reseat them.) Not saying it's not a card problem but it seems more like a heat problem.

  keith-236785 06:41 26 Jun 2003

ok mate back to basics

remove all cards except graphic card

disconnect all drives from motherboard

disconnect all case header wires (except case speaker) from motherboard

disconnect any extra fans you have EXCEPT THE CPU FAN

unplug any USB devices/printer/modem/lan cards

so you should have floppy, memory, cpu + fan, graphic card, keyboard and mouse.......NOTHING else connected

try to boot up, if it still wont work then i would suspect a power supply problem, Does it beep at boot up?, if it does boot then you can start to connect things (one at a time and try to boot, HARD DRIVE first, then cd rom, then cdrw/dvd if you have one.

continue until you find it wont boot then go back one step and try again.

good luck

  Bodi 08:12 26 Jun 2003

Check the BIOS/Power Up Control settings.

There was someone on here a good few months ago whose computer started up every time the telephone rang. The Pwr Up On External Modem Act was set to -ON- - disabling this solved the problem. Also check to see if the Power Management in the BIOS (maybe set to - User Defined -) is set to - minimum -

You could also check the boot sequence in the BIOS.

Once you have eliminated a BIOS problem - could set these to Default/Factory settings, then try changing flat cable ribbons to hard drives/floppy etc. The irritating thing about computers is that it is a process of elimination and bet your bottom dollar, the problem is caused by the last thing you check. Anyway, try the simple things first and make a check list or you end up going round & round in circles.

Frustrating little beasties aren't they?


  Bodi 08:15 26 Jun 2003

You could also try a new memory module and/or spare graphics card.


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