Strange computer startup problem. Help!

March 3, 2011 at 09:59:29
Specs: Windows XP Pro, Amd 3500 - 1Gb Ram
Hey guys, I need help!

Whenever I go to turn on my PC, I first have to unplug it and press the power button a couple times/hold it for a few seconds, then plug it back in before it will turn on. It starts and runs fine after this, but I'm obviously confused as to why it's doing this.

I had the PSU replaced recently, as it stopped working completely (I went to the computer shop that originally assembled the PC for me), while there I also had the CMOS battery replaced, which had died months before.

The computer started fine in the shop, got it home and nothing...

Took it back the next day, and it wouldn't start in the shop either. The technician checked the comp with a different power supply, it worked. He then reconnected the PSU and it Booted! Shut it down, and started it up again. He said it may be the cd-rom drive, so left it unplugged, and told me to see how I got on.

I got it home, plugged it in, and nothing...
I tried a different outlet and it worked! I then used it most of the day, and then shut down. Just out of curiosity I decided to see if it would start. It wouldn't...

I started looking for answers on the web, and came across the pressing the power button/holding it method. Tried it, it worked!

And that's where I stand atm.
Whenever I want to use it I have to go through the little routine.

There are a few things I've noticed though...
1) If I shutdown the comp then restart immediately, it boots back up. However if I shut it down (leaving it plugged in), and try turning it back on after 5-10 minutes it doesn't turn on...
2) When it's left unplugged over night I still have to press the power button/hold it for a few seconds to discharge any static (if that's what its doing) before it will turn on when plugged in.

When it's on it runs fine, no signs of concern or anything, which confuses me even more.

So yeah, sorry if this is rather long winded, but I know the more detail the better.

I'd really appreciate any advice you can offer. I'd like to have an idea of what it could be before going back to the shop, just so I'm not going in clueless.

Anyway, thanks for reading!

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March 3, 2011 at 10:25:14
Were all components new when this computer was assembled?

There could be any number of reasons for that behavior.

I would suspect the power supply but you have already kind of eliminated that as the problem.

A cold solder joint on the motherboard or a poor connection between any of the connections or components is another.

Try unplugging all wiring connection and reconnecting. Remove and reinsert the graphics card, if one is installed. Snap all the RAM modules in and out 4 or 5 times to burnish the contacts.

Check the RAM voltage and verify that is the voltage the BIOS is set to. You can use a utility called SIW to determine the specs for each RAM module, including the required voltage. All must be the same specs and the BIOS settings must match.

Because the motherboard is new this would be highly unusual but bad capacitors on the board can cause that kind of behavior. Look for any bulging or leaking on the capacitors. See the link below for pictures.

If the motherboard is shorting out on the case that can cause problems. The most common reason for that is using a case with stamped raised bosses as mounting points, instead of the more common metal screwed in standoffs. If your case has raised bosses you need to place fiber insulators between the case and the board.

Be sure the issue is not with an external piece of hardware by removing all non-essential components like printers, scanners, external drives, memory cards, flash drives, etc.


After rereading your post I have other points to make. If the computer worked fine prior to the power supply going out then the power supply may have damaged the motherboard or other components.

Was the computer subject to a power surge or lightning strike?

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March 3, 2011 at 10:45:05
Hey OtheHill, thanks for the speedy reply!

In an effort to put detail in seems like I overlooked the basic information! Let me clarify...
I've had the computer about 5 years now.

It worked fine, up until a few days ago.

I have it plugged into a surge protector, but when the original PSU went there were no signs of life at all. Once the PSU was replaced the computer works, but has to have the power button pressed/held before being plugged in, then switched on.

There have been no lightning strikes and the surge protector is still working fine. However, if the original PSU went, could this have damaged the motherboard or another component?

I'll do a visual inspection on the mobo, using that guide (much appreciated).

Just out of curiosity, what would pressing the power button/holding it when unplugged be doing? What is allowing it to work after that process? And is that a sign that, although working at the moment, that something is failing or will fail in the near future??

Once again, thanks for the reply!!

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March 3, 2011 at 10:57:39
As I stated, the power supply failure may have damaged other components. The motherboard is the next component in the chain.

Pressing the power button while the computer is unplugged will discharge any residual power left in the power supply components. As I stated, I would have suspected the power supply except for the fact they tried more than one with similar results.

Wouldn't hurt to perform the re-seating as described above.

I had a system that gave me similar problems and it turned out to be a defective add in graphics card that eventually died all together.

When a power supply goes out they sometimes go out with a bang. A power surge to the various components. One thing I didn't mention that I just thought of. With the computer unplugged, remove the large power supply to motherboard connector (there is a locking tang you need to depress and hold). Then examine the socket on the motherboard for any arcing or burn marks. Obviously the motherboard still works but there could be a bad contact in that area.

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Related Solutions

March 3, 2011 at 12:52:54
Have checked the motherboard, no signs of bad capacitors, or burns.

Everything seems to be connected securely.

Very confusing!

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March 3, 2011 at 13:07:23
Did you try re-seating everything?

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March 3, 2011 at 13:16:08
No, not yet.

Am I ok doing that (i'm a bit of a rookie)? Anything I should be aware of when doing it?

Any order I should do it in?


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March 3, 2011 at 13:48:26
You don't need any order. Just don't remove more than one wire at a time. The single wires from the case to motherboard are probably not necessary. Mostly the memory and any add in cards (the ones with screws into the case) you may have installed on the motherboard. Just be sure you unplug. Depressing the start button after unplugging is a good idea too. If your power supply has an ON/OFF switch on it then use that and leave the plug in the wall. Doing that maintains a ground. Touch a metal part of the case before reaching inside. Care should be taken about static discharge. That is the purpose of toughing the case.

If the computer is 5 years old the memory probably could use the burnishing. As I said above. Just snap each one in and out 4 or 5 times. Be sure they are fully seated when finished.

One other thing, the CPU fan is connected to a header marked CPU fan. Unplug and replug that one. Also if there is a square 4 wire connector from the power supply directly to the motherboard then do that one. If there is a wire to any add in graphics card do it too.

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March 3, 2011 at 13:58:46
Ok, will give it a go!

I'll reply either way tomorrow, wish me luck!

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March 3, 2011 at 14:47:53
Alas, no success!

Everything re-seated successfully :-)

But still got the same start-up issue.

I really appreciate the advice though!

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March 3, 2011 at 20:06:06
OK lets recap. This start up issue didn't appear until AFTER the power supply went out?

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March 4, 2011 at 10:25:57
Correct, after the original PSU was replaced (which showed no signs of life), this problem started happening.

Once it's on it works fine. It's just the initial turning on of the machine.

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March 4, 2011 at 12:28:00
Have you tried watching what happens in the case when you turn on the computer? If the CPU fan does not immediately start rotating the computer is not going to start.

It might be a pain but I suggest you remove the motherboard from the case and set it on cardboard on the opening of the case. See if the problem persists. While the board is out, look at the mounting area. Are there metal machined posts screwed into the case at all points where screws penetrate the board and ONLY where screws penetrate?

Write back what you see.

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March 4, 2011 at 14:50:29
I've watched what happens when I turn on the comp. Everything starts fine, all fans working. Before pressing the button a few times there are no signs of life though.

If the computer worked fine for 5 years, is it likely to be one of the mounting points? When the PSU was replaced the motherboard wasn't moved and it feels secure.

The only reason I ask is, to a rookie, it seems like quite a daunting task to remove the whole motherboard. Are there any other alternatives it could be before attempting this?

Thanks for the help!

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March 4, 2011 at 20:07:24
Can you see if the mounting plate has the raised bosses by looking at the back side (underside of motherboard). Cheap cases with those raised bosses can cause parts of the motherboard to ground out because there is too much surface area. The motherboard is actually supposed to be grounded to the case by means of touching in the correct places.

If you don't want to remove the board there are other things you can try. You need to see if any of the hardware is causing the non-start issue. The power supply is one suspect. Bad or shorted motherboard is another. Those either cost money or work. You can check the memory using a utility that runs through every bit of the RAM. You download a file and install it to CD or flash drive and boot to it. You need to verify your computer is capable of booting to a flash drive before bothering to prepare one.

memtest86+ is a good one to use. Link below.

Download the free version of SIW and check the SPD for the RAM. Post the results here.

SIW at the second link below.

If you don't feel up to prepping a CD or flash drive there is a Windows version there too.

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March 5, 2011 at 10:02:33
Have used SIW, which part of the results should I be posting? The memory section?

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March 5, 2011 at 12:07:27
Yes the SPD for the memory along with the rest of the memory specs.

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March 5, 2011 at 12:10:51
Here It is:

Memory Summary
Maximum Capacity 4096 MBytes
Maximum Memory Module Size 1024 MBytes
Memory Slots 4
Error Correction None
DRAM Frequency 201.0 MHz
Memory Timings 3-3-3-8 (CL-RCD-RP-RAS)
Device Locator Slot 1
Manufacturer Corsair
Part Number VS1GB400C3
Capacity 1024 MBytes
Memory Type DDR (PC3200)
Speed 200 MHz
Supported Frequencies 200.0 MHz
Memory Timings 3-3-3-8-0 at 200.0 MHz, at 2.5 volts (CL-RCD-RP-RAS-RC)
Data Width 64 bits
EPP SPD Support No
XMP SPD Support No


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March 5, 2011 at 12:35:29
RAM appears to be built to JEDEC standards. I was concerned the voltage might be non-standard. If the RAM voltage shows in one of your BIOS (setup) screens, verify that it is running at 2.5V. If the RAM is set to auto it will be grayed out but still readable.

Is your computer a branded or custom computer. If branded post the brand and full model. If custom post the exact motherboard model. SIW should show that information.

Post any information listed in SIW for the Graphics.

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March 5, 2011 at 13:08:35
Can't seem to find the RAM voltage on the BIOS, any specific section i should be looking in?

The computer is custom, the mother board is a Asus A8N-SLI Deluxe.

Video Adapter NVIDIA GeForce 6600
Code Name NV43
Video Processor 47 00 65 00 46 00 6F 00 72 00 63 00 65 00 20 00 36 00 36 00 30 00 30 00 00 00
Technology 0.11 ┬Ám
Adapter DAC Type 49 00 6E 00 74 00 65 00 67 00 72 00 61 00 74 00 65 00 64 00 20 00 52 00 41 00 4D 00 44 00 41 00 43 00 00 00
PCI ID 0x10DE / 0x0141 (nVidia Corporation / GeForce 6600)
PCI sub ID 0x107D / 0x2001 (LeadTek Research Inc.)
Memory 256 MBytes
Type DDR
Memory Bus Width 128 bits
Performance Level 3D Applications
Core Clock 300 MHz
Memory Clock 500 MHz
Bandwidth 8000 MB/s
BIOS String Version Version Version Version
BIOS Date 05/05/20
DirectX DirectX 9.0
Driver Name nv4_disp.dll
Driver Description NVIDIA GeForce 6600

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March 5, 2011 at 14:41:47
I downloaded your manual. The RAM voltage doesn't appear unless you set the RAM configuration to manual. Don't worry about that.

Did you need to enter the BIOS screens at any time since this problem arose and make any changes?

What type of optical drive and hard drive/s do you have?

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March 5, 2011 at 15:53:38
No, I haven't altered anything in the BIOS since the problem arose.

I have a Samsung DVD-rom drive, which was unplugged as the techincian believed this may have been causing the problem. However, the problem has still continued, even with the DVD-rom unplugged.

The HDD is 80gb, seems to be working fine atm.

Really appreciate the continued help!

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March 5, 2011 at 16:57:42
Are they SATA or IDE ATA type drives? SATA uses smaller red data cable. IDE uses wide white ribbon type cable.

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March 6, 2011 at 05:54:22
Sorry for the delay, have been away from my comp (and will be until tomorrow now), but just checked.
The HDD is a Maxtor 6Y080M0, Serial ATA.

The DVD-ROM has the same cable type also.


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March 6, 2011 at 06:14:40
SATA data cables can be damaged or impaired by folding them too tightly. If you have the surplus cable folded neatly I suggest you undo it. No tight bends and no running parallel to other wiring if possible.

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March 16, 2011 at 13:28:02
Hi again, really sorry for the gap in replying, those few days turned into more than a week (and still ongoing), so i aplogise in advance if my replies are patchy.

I checked the cables though, and they all seem to be fine.

Another thing i feel i should add, i don't usually do it that often, but i put the computer on standby for the first time since this problem arose. However, when i come back to use it, it no won't awaken, and have to then unplug/press button a couple times to get it to startup again.


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March 16, 2011 at 13:39:37
Without reviewing this entire thread I will ask, did you try everything I suggested including the memory test?

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