Member Avatar for coconutpalm

Hello. Recently, I am having a startup problem on my Windows XP machine, and I am hoping someone can help.

When I start the machine, sometimes it starts up just fine. No problems. Other times, the green POWER LED comes on, then I can see the CD-ROM access LED coming on, then may be sometimes I can see the floppy drive access LED coming on, then suddenly the machine goes dead, and the green power LED goes off.

OS: Windows XP SP2
Power: ACPI-compatible
RAM: 512 MB (2 separate 256 MB cards, second card installed much after the first)

Is this some kind of mechanical issue with the power switch (ACPI compatible) or is it faulty RAM? If the RAM card is faulty, any easy way to figure that out? I would appreciate any help. Thanks.

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  • Latest Post Latest Post by jbennet

Dani AI

Generated

Intermittent shutdowns during early POST most often point to the power-delivery path or an intermittent connection on the motherboard rather than Windows itself. Given the sequence described earlier and ’s later note that a technician fixed the board (without swapping the CMOS cell), the most useful next steps are targeted, low-risk checks that let a non‑specialist isolate the fault before buying parts.

Start with a minimal, stepwise isolation:

  • Remove non‑essential devices and boot with only CPU, one DIMM, video (if needed) and the PSU connected. Add devices back one at a time to spot the culprit.
  • Bypass the case power switch to rule out the front-panel: momentarily short the two power‑switch pins on the motherboard to simulate the button (use an insulated screwdriver and take basic safety precautions).
  • Inspect the board closely around the ATX and CPU power sockets for bulging/leaking electrolytic capacitors, burn marks, or cracked solder joints. Visual signs often point straight to failing power circuitry.
  • If comfortable and equipped, measure PSU rails or use a simple PSU tester: +12V and +5V should be within a few percent of nominal. If not confident, skip this and get a professional check — improper measurements can be dangerous.

Notes and cautions:

  • Intermittent failures that stop when a board is warm often indicate marginal solder joints or aging capacitors; a technician’s “fiddle” frequently equates to reseating connectors, reflowing joints or replacing caps.
  • CMOS battery issues rarely cause sudden power loss during POST; they more commonly affect time/settings or BIOS defaults.
  • If the problem is intermittent and hardware tests are inconclusive, request the technician to document exactly what was repaired so future troubleshooting is easier.

Recommended Answers

All 14 Replies

Member Avatar for zelkea

How is your system performing when you are able to boot? Is the system stable until you reboot? Heat can be another culprit for the issue you described. Check your CPU fan and vents. If you would like to test your memory you can use memtest86 http://www.memtest.org/ .

AJZ

Member Avatar for RueB2sDe

I would agree AJZ. Possible heat issue on the CPU fan. May need to be to dusty inside causing the FAN to slow down or it could be a Power supply issue. Power supply may need to be replaced.

RueB 2s De

Member Avatar for gerbil

i would be very suspicous of your power supply. It issues a PS Good signal to BIOS which triggers bios execution and so on. If it then cannnot handle the load of assorted operations it will cut the signal. Everything just stops. No warning.

Member Avatar for coconutpalm

How is your system performing when you are able to boot? Is the system stable until you reboot? Heat can be another culprit for the issue you described. Check your CPU fan and vents. If you would like to test your memory you can use memtest86 http://www.memtest.org/ .

AJZ

zelkea, as per your advice, i downloaded memtest86 and ran it for five hours on my machine. not a single RAM error was reported. so may be i should assume that my RAM (2 256 Mb cards) is fine and not the problem point.

the system is very stable other than this startup problem. crashes are extremely rare.


I would agree AJZ. Possible heat issue on the CPU fan. May need to be to dusty inside causing the FAN to slow down or it could be a Power supply issue. Power supply may need to be replaced.

RueB 2s De

i would be very suspicous of your power supply. It issues a PS Good signal to BIOS which triggers bios execution and so on. If it then cannnot handle the load of assorted operations it will cut the signal. Everything just stops. No warning.

may be i should take the external casing out and clean the area of the CPU fan and vents. i could also look at the power supply. as a temporary solution, i am using my laptop instead of the errant desktop.

thank you.

Member Avatar for zelkea

A can of compressed air should be good enough to clean out the dust. Most motherboards have a led on the board that is on whenever the system has power. When your system fails is the led light on?

AJZ

Member Avatar for coconutpalm

A can of compressed air should be good enough to clean out the dust. Most motherboards have a led on the board that is on whenever the system has power. When your system fails is the led light on?

AJZ

I will take the casing out and clean the dust on the desktop sometime in the next two weeks, and hope that solves it. If that doesn't work, I will check the power supply.

When my system fails, the motherboard LED goes off.

Sometimes machine boots fine.

Other times, machine doesn't boot. I will give you more detail on what goes wrong when it doesn't boot:
Step 1. I switch on the POWER LED on the front panel.
Step 2. POWER LED goes green.
Step 3: CD-ROM access LED comes on. Floppy Drive acess LED comes on. At the back, the fan starts whirring. (My boot sequence is CD-ROM -> Floppy -> Hard Drive.)
Step 4: All the lights including POWER LED go dead. Fan stops whirring.
Step 5: So now I am thinking will this darn thing start up or not.
Step 6: I press the RESET switch once.
Step 7: I switch off the main UPS switch.
Step 8: I switch on the main UPS switch.
Step 9: Try to switch it on a few times, often in vain.
Step 10: Take a coffee break.
Step 11: After some frustration and repeating the above sequence, the machine switches itself on.

Member Avatar for dcc

Do you have another PSU that you can try? It does sound like the PSU may have a problem, then again it could be the motherboard.

Member Avatar for RueB2sDe

Do you have another PSU that you can try? It does sound like the PSU may have a problem, then again it could be the motherboard.

Yah I would start with the Power supply. If all else fails with replacing the powersupply try your CMOS battery before you replace anything major like a motherboard.

If you don't get any errors when the system boots, I sounds like it is going through the boot sequence correctly. (just to let you know you can switch your boot sequence if you removed the CD rom from the boot sequence it would not effect this issue)

The CMOS Battery will effect your system by not powering up or minimal power to the devices connected to the motherboard.

Removing the dust on the Heat sink (the Fan above the CPU) and any dust inside the tower it will allow the devices to function better.

Power supplies are inexpensive and if you replace it, and it doesn't work you can return it normally to the store for a full refund.

RueB 2s De.

Member Avatar for coconutpalm

thanks everybody. i haven't been switching off the desktop recently. i just keep it running 24/7, having switched off standby/hibernation.

in a couple of weeks, i will get around to trying a new Power Supply Unit.


Do you have another PSU that you can try? It does sound like the PSU may have a problem, then again it could be the motherboard.

Yah I would start with the Power supply. If all else fails with replacing the powersupply try your CMOS battery before you replace anything major like a motherboard.

If you don't get any errors when the system boots, I sounds like it is going through the boot sequence correctly. (just to let you know you can switch your boot sequence if you removed the CD rom from the boot sequence it would not effect this issue)

The CMOS Battery will effect your system by not powering up or minimal power to the devices connected to the motherboard.

Removing the dust on the Heat sink (the Fan above the CPU) and any dust inside the tower it will allow the devices to function better.

Power supplies are inexpensive and if you replace it, and it doesn't work you can return it normally to the store for a full refund.

RueB 2s De.

Member Avatar for gerbil

24/7. You must be rich. Semiconductors age as current runs through them... of course switching things on/off every 10 minutes is not good either cos thermal shock is another wearntear factor. There is a good medium somewhere in there; my pc takes way under a minute to boot up and I find I can utilise that time in any number of ways. And if I'm going to be away for more than, say, an hour, off it goes. And I have all standby schemes enabled! Up to you.

Member Avatar for coconutpalm

I changed the SMPS, but that did not solve the problem. So I gave it to my friendly local technician who fiddled with the motherboard and solved my problem. My computer now boots without problems. He told me that he did NOT replace the onboard CMOS battery. However I am not sure what the technician did, and I did not ask.

Member Avatar for jbennet

24/7. You must be rich. Semiconductors age as current runs through them... of course switching things on/off every 10 minutes is not good either cos thermal shock is another wearntear factor.

1 reboot puts the same amount of wear on the HDD as 16 hours of average use. Thats a lot. PSUs are cheap, hdds arent

Member Avatar for gerbil

1 reboot puts the same amount of wear on the HDD as 16 hours of average use. Wow!... i didn know that. wasn thinking of the psu tho, more every other lil semiconductor pasted here n there. processors, etc. So where is the hd wear? nothing touches, cept maybe on the rest zone b4 it speeds up... i think...
M$ could be in cahoots with hd manufs cos of that auto reboot on error setting... :) - don't ever go on hols n leave your sys on.

Member Avatar for jbennet

im pretty sure that figure is accurate. Ive had my server running since like 2001 (before that it was running since like 98) and its still running fine. Its had about 12 reboots whereas my 3 year old dell which is rebooted constantly died recently of hdd failure

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