# CPU Won't Turn On: Green Light On Motherboard...?



## parabolate (May 30, 2005)

Hello all,

My Problem:

Tonight I went to turn on my PC and the machine was "dead" so to speak. No fans/drives attempting to boot up or anything, even momentarily, just a completely dead machine. In addition to the machine being "dead", I noticed that there is a green light on the motherboard that remains on when the machine is plugged in with the PSU turned on.

Things that I have done to try to fix this:
-Change the wall socket the power cord is connected to
-Check to make sure all cable connections inside the PC are secure
-Check to make sure the power button itself is connected correctly
-Check to make sure the PSU switched on (duh) and set to correct voltage
-Check to make sure RAM and other components are seated on the MB securely

Obviously, none if this has brought my PC back to life so I am wondering what could be causing this? The PC was not moved or anything recently and no hardware / software changes of any sort have been done recently.

However!....(I dont know if this is worth mentioning or not) it might be helpful to make the following known: about 1 to 1 1/2 month prior to this occurring I had a similar problem where my PC would turn on briefly then turn off after funky colors on the monitor displayed.....then eventually it died completely and wouldn't even *attempt* to boot. My PC manufacturer sent me a brand new video AND PSU b/c they were not sure what was causing it. Sure enough, after installing a the new video and PSU the PC came back to life.

This time.....the P/C just died.....and I have this green light on the MB. SO, this is the second time this PC has "died" and I am not sure if the two incidents have any relation to one another or if its a completely seperate problem. What a PITA I gotta say lol..... 

What do you think could be the cause of this? Any ideas?


System Specs:

Operating System: Windows XP
Motherboard: ASUS A8N5X
RAM: 2x 512mb (1gb Total)
Video: ATI Radeon x1600 Pro
Power Supply: 400w
Hard-Drive: 160gb


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## solman (Aug 17, 2005)

parabolate said:


> ...what could be causing this?
> However!....(I dont know if this is worth mentioning or not) it might be helpful to make the following known: about 1 to 1 1/2 month prior to this occurring I had a similar problem where my PC would turn on briefly then turn off after funky colors on the monitor displayed.....then eventually it died completely and wouldn't even *attempt* to boot. My PC manufacturer sent me a brand new video AND PSU b/c they were not sure what was causing it. Sure enough, after installing a the new video and PSU the PC came back to life.
> 
> This time.....the P/C just died.....and I have this green light on the MB. SO, this is the second time this PC has "died" and I am not sure if the two incidents have any relation to one another or if its a completely seperate problem.
> ...


I have had two bad PSUs in a row...Well actually, I've had four bad PSUs in a row. What are the exact specs on the PSU? There will be a white sticker on the inside of the case documenting this.

Are you connecting through a surge protector or directly to the wall outlet?

Branded PC manufacturers typically ship the bare minimum requirements for the PSU so it's highly likely that you're just getting crappy PSUs.

A few things to check would first be to make sure you have the RAM seated in the correct DIMMS. You have dual channel on your MB so the RAM should be seated in DIMM0, DIMM2 or DIMM1, DIMM3 however your DIMMs are labeled. For example, the first module should be in the first Blue DIMM(Closest to the Processor) the second module should be seated in the #3 DIMM (the other blue socket, 3rd from the processor).

You should reseat these any way even if they are in the correct location and reset your BIOS after this is done.

Also, what AMD processor do you have?

And finally, when you received the new PSU did you plug the 4 prong +12v in near the processor?


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## dai (Jul 2, 2004)

it's doubtful a 400w would have enough amps output on the 12v+line for stability


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## parabolate (May 30, 2005)

solman said:


> I have had two bad PSUs in a row...Well actually, I've had four bad PSUs in a row. What are the exact specs on the PSU? There will be a white sticker on the inside of the case documenting this.
> 
> Are you connecting through a surge protector or directly to the wall outlet?
> 
> ...


To answer your questions:


No surge protector.
Yes the 4 prong +12v is plugged in.
Processor is AMD athlon 64 3500+

*UPDATES ON THIS PROBLEM:*

I found out that my father was tampering with the RAM in the PC in question. I talked to him today about the PC problem and he said he was trying to put RAM from an old PC of ours into the computer. Sure enough upon closer inspection the RAM in the PC was simply not seated correctly.

No big deal right? *sigh of relief* or so I thought...

I reseated the RAM, dusted up a bit, and now the PC was powering up but would not POST. I was getting one long beep and two short beeps. From what I could find online this signifies a "video failure". The video card was working just fine prior to this incident so I'm not sure why that would be happening all of a sudden.

I tried to reset CMOS but I dont seem to be having any luck with that - it didnt seem to be doing anything. I did exactly as my my particular MOBO manual said to do it: removing battery and moving the the pin cover from 1-2 to the other pins 2-3. I also tried methods I found online including just letting the battery sit out for a long time. Still would not POST after several attempts of doing this.

Well...after getting nowhere with that I tried booting with just one stick of RAM in at a time. Surprisingly the machine now boots to BIOS on one particular stick of RAM. The machine will NOT boot with the other "bad" stick alone or with the other stick accompanying the "good" stick so I guess this stick may somehow have gone bad when my dad was screwing with it? 

Anyway, having said all there heres where I'm stuck currently....the system boots to BIOS with the following error prior to continuing to BIOS: "Warning your comp CPU fan fail or speed is too low. You can disable is setup. F1 to continue." F1 boots to BIOS where the fan warning setting is set to 800ROM. I disabled that for now.

After restoring defaults in BIOS accept for that fan setting the PC looks like it is going to boot but then goes to a black screen on the monitor with "No Signal Detected".

So RAM that has gone faulty somehow is no longer in use during this troubleshooting process. I'm now getting the CPU fan warning. And of course the main issue here which is the No Signal Detected when trying to boot to WinXP or safe mode. No more long beep-short beep-short beep when attempting to boot, just that signal error. I get the single POST beep.

Im not sure exactly how these issues may or may not relate to one another and Im not sure where to go from here. LOL....

Thanks for the help so far guys!....What step should I take next?


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## dai (Jul 2, 2004)

if you are receiving the cpu fan warning it is probably shutting the cpu down to protect it from overheating


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## parabolate (May 30, 2005)

dai said:


> if you are receiving the cpu fan warning it is probably shutting the cpu down to protect it from overheating


Yeah. As I mentioned I disabled the fan warning in BIOS setup just to try and get a boot to the OS going but that didn't work. Visually I can see the CPU fan spinning quite fast but it apparently isn't going faster than 800 RPM according to the BIOS. 

What I'm not understanding up to this point is how what seemingly originated as a simple RAM issue (the one stick is now apparently "bad" as the PC wont boot with it connected) is now an issue involving the CPU fan and the video card b/c of the "No Signal Detected" I am getting after trying to boot to WinXP or safe mode.


It is unclear what the root cause of it all is. Surely the RAM stick, video card, and CPU fan could not have all failed/started having problems at once? :4-dontkno


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## dai (Jul 2, 2004)

what psu do you have in it and how many amps is it putting out on the 12v+ line


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## parabolate (May 30, 2005)

dai said:


> what psu do you have in it and how many amps is it putting out on the 12v+ line




It is a 400w PSU.

I don't have access to the PC in question at the moment (at a different location right now). How will I be able to tell how many amps it is putting out on the 12v+ line? Will it show this info in the BIOS?

Also, if it's worth mentioning. The PC worked fine for about a month and 1/2 before this incident on the current PSU. Prior to using the 400w I used a 350w for a little over a year then it died. Guess it wouldn't be terribly surprising if this one is having issues too.

Thanks!


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## dai (Jul 2, 2004)

look on the label on the side of the supply for the 
brand
wattage
amps on the 12v+ line


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## parabolate (May 30, 2005)

dai said:


> look on the label on the side of the supply for the
> brand
> wattage
> amps on the 12v+ line




Atlas "Safe Power" 
400w
20 amps on 12v+


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## dai (Jul 2, 2004)

it does not put out enough amps on the 12v line for pcie
pcie=24amps
see if you can borrow a quality 550w psu to try in it
http://www.techsupportforum.com/showthread.php?t=107466


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## parabolate (May 30, 2005)

dai said:


> it does not put out enough amps on the 12v line for pcie
> pcie=24amps
> see if you can borrow a quality 550w psu to try in it
> http://www.techsupportforum.com/showthread.php?t=107466


I don't have a 550w PSU to try in it. I'll probly send it back to the company and request the higher wattage PSU as this 400w PSU was sent to me in order to replace the old 350w PSU that was originally in the system.

In your opinion is it likely that the PSU is what was causing all of the other aforementioned issues? (The seemingly "now-gone-bad" RAM stick, video signal error upon attempted OS boot, and the CPU fan warning in BIOS).


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## dai (Jul 2, 2004)

the psu can cause all kinds of problems


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