Member Avatar for Kate123

Please please help!

I recently installed a new socket 478 motherboard in my 2ghz P4. Everything went well until i tried to install a video card. Then the pc wouldn't recognise the hard drive. I figured this was the psu and got a new one but computer wouldn't work with the new psu and video card. I then put the old psu back in the pc and it booted up to windows but shut itself down. I have taken the video card out but now the computer won't start at all. when you turn it on the fans and lights start for a few seconds but then it shuts itself down. i can't plug in the internal speaker as it is not compatible with my new motherboard so i can't diagnose anything from beeps on start up.

Cheers Kate

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Dani AI

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Good diagnosis so far: found the sticking power switch (that explains the immediate shutoffs), and was right to suggest RAM checks. The remaining symptom set — fans and lights for a few seconds, no POST, brief keyboard activity, and “drive disappears” when a discrete card is fitted — most often indicates one or more of: insufficient or flaky PSU, corrupted/weak CMOS battery or BIOS settings, front-panel/header wiring or a board short, or a marginal component (RAM/CPU/drive).

Quick, ordered bench checklist (do these one at a time):

  1. Minimal bench boot on a nonconductive surface: CPU + heatsink, one stick of RAM (try each stick), onboard video or one known-good card, PSU connected, monitor attached. Remove all drives and extras.
  2. Swap in a known-good PSU or use a PSU tester. A 185W unit is strongly undersized for a discrete video card + optical drives; use a quality supply (300–350W or more for systems with GPUs) to rule out brownout under load.
  3. Verify the motherboard’s ATX12V/CPU 4-pin power is plugged (many P4-era boards need it).
  4. Proper CMOS clear: use the clear jumper or remove the coin cell for several minutes — replace the CR2032 if the problem recurs (frequent clears mean a bad battery or corrupt NVRAM).
  5. Confirm front-panel wiring and try momentarily shorting the power pins to rule out a faulty case switch (power off and unplug when changing connectors).
  6. Check for shorts: ensure standoffs are correct, no stray screws, and the board isn’t touching the case. If a drive disappears only when a GPU is added, that is classic PSU-load behavior.

If POST still fails, add a simple PC speaker for beep codes and test the HDD in another computer to confirm it’s healthy. BIOS updates are a last resort — only after hardware is proven stable, and follow the board maker’s instructions. In this thread the most likely root causes are power (PSU) and CMOS/battery; start there.

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Member Avatar for sittas87

Hi
Fisrt make sure all youre components are compatible with your mobo. Within regards to you CPU make sure it has enough greese on it. If all is in tact then swop around youre RAM one at a time and in different slots. After doing all the above with nno avail remove your cmos and keep it out for a couple of minutes,replace and see if theres any changes

Member Avatar for Kate123

Thanks for the reply!

Mixed news!

I found out why the pc keeps shutting itself down. The old power switch wasn't compatible with the new motherboard so i had to by a new switch. The new switch was sticking everytime i turned it on. Phew!

HOWEVER; i still have a problem. When the pc is switched on the fans start spinning and the drive lights come on but it doesn't POST. The monitor receives no signal the there are only brief lights to the keyboard.

This has happened before when i tried to add an extra dvd drive to the new motherboard. i fixed it by removing the cmos battery for several hours and removing the additional drive. The PC then booted normally.

As i said before in my previous post if i try to add a graphics card the pc then won't recognise the hard drive. It POSTs but then can't locate the hard drive to boot into windows.

I've found that removing the cmos for several hours fixes these problems but it means i can upgrade my pc at all. Any suggestions? I still think it is the power supply. i'm guessing the new moterboard, asrock socket 478, is using a lot more power than the old one and the psu can't power and addtional components.

Member Avatar for sittas87

in actuall fact I have a 478 socket and believe it or not I have a 350 watt Power Supply. yes that works and as far as I know it supplies power for all my componants. whats your psu wattage though

Member Avatar for Kate123

185W!!!

Not much at all.

Member Avatar for sittas87

see if you can find psu with aminimum of 350 wattage. you may be right after all, I didnt realise youre psu's output was that little.

Member Avatar for easter1

my gateway computer is keep shutting off randomly and restarting.i formatted the hard disc but still it has the same problem.please help what could be the reason?

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