PC wont boot

  Commander Straker 14:57 10 Jan 2010

My niece has asked me to fix her PC.....its quite old but not sure of exact spec but think its a Pentium rather than AMD.

Pc turns on, and fans operate in PSU and motherboard (processor), but nothing appears on screen and no BIOS beeps. All components are seated correctly and all connectors have been reconnected to ensure contact. Before this PC was freezing (would accept no keyboard or mouse input) or turned itself off.

I think its the PSU at fault but would welcome other views.....many thanks.

  OTT_Buzzard 15:26 10 Jan 2010

PSU sounds about right to me.

  OTT_Buzzard 15:26 10 Jan 2010

Worth resetting the CMOS just to make sure though.

  Fruit Bat /\0/\ 15:33 10 Jan 2010

REmove and refit graphics card to remake connection- retry

try another monitor.

1. Overheat due to faulty / blocked fans

2. PSU voltages

3. Household power surges fridge etc switching on/off

4. faulty memory stick try memtest click here

5. virus or spyware scan for both especially if shutting down with in a few minutes of switch on or internet use

6. driver conflicts especially grahics cards get the latest drivers for your equipment

  Diemmess 15:34 10 Jan 2010

A very simple thing to try.....
In view of its previous behaviour this may not work.

Switch off and remove mains plug from the back of the case.

Press and hold down reboot button for 20-30 seconds.

Replace the mains plug, cross any spare fingers switch on the box as usual.

  Commander Straker 19:58 10 Jan 2010

Thanks all for quick responses. For info screen, keyboard, power cable are all from one of my own working computers of similar vintage but fault is replicated. I will try a PSU replacemnet as I am unable to get any life out of it to download drivers or make a memory test.

  DieSse 20:12 10 Jan 2010

Commonest things that produce no actual booting are

Faulty RAM

Faulty Motherboard

Processor needs reseating in socket (bad connections)

Faulty PSU

Plus a whole host of lesser probabilities

  OTT_Buzzard 20:25 10 Jan 2010

Before you get a new PSU, it's worth checking DieSse's suggestions.

Check the capacitors on the motherboard - they should all be planted neatly and firmly on the motherboard. If one or more has 'lifted' off, and especially if there is any blackish residue underneath them, then the motherboard is dead. There are a number of other failures that could occur on the motherboard, but capacitors are the easisest to check and the most likely to have failed.

If you have another PC that will take your RAM then swap the RAM stick over and check.

If the processor needs reseating, do so, but make sure to reapply thermal paste.

  Commander Straker 21:31 18 Jan 2010

Another PSU made no difference. Another BIOS battery made no difference. Cant check the RAM but all seating checked and okay. Cant see anything wrong with motherboard. Cleared all dirt from fans etc. I'm thinking its going to be a non starter.....probably a Motherboard fault........so will uninstall the HDD drive and install in another machine to get the files.

  Quiller. 21:49 18 Jan 2010

Disconnect hard drive / cdrom / floppy drive cables from the rear of the devices. If the motherboard has a graphics card and an onboard graphics slot. Take the card out and connect to the onboard graphics slot. Take out any PCI cards, i.e. cards in the white slots. If the motherboard is that old, take out any ISA cards. Just use one stick of memory at a time. Do not connect mouse or keyboard.

See if it POSTs.

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