No POST, no boot

lmgoldin used Ask the Experts™
I have a computer here that won't boot. It doesn't make any of the usual startup sounds, nothing appears on the screen, there are no beep codes. It is getting power, since the fan on the video card runs and the power supply seems to be running. I was told that the computer ran before I got it, but that it kept rebooting itself over and over.
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Top Expert 2012

Unable to boot:

If it's an AMD system:
The first thing to check is if you plugged the cpu/heatsink fan into the motherboard header, because most AMD motherboards check if there is a working cpu fan before they will start.

- faulty or inadequate power supply
- bad connections
- faulty video card
- bad RAM
- bad cpu
- bad motherboard

To troubleshoot this, I recommend stripping down the pc to the bare essentials: install one stick of RAM, the cpu, and the video card, and reset the BIOS after installing the cpu.  Do not include hard disks, other PCI cards, or other peripherals.

If this doesn't start up, swap the video card.
If it still doesn't start up, swap the power supply.
If it doesn't start up at this point, you may have a faulty cpu or motherboard.  The cpu can be tested by trying it in another system; the motherboard really can't, and you would point to it when everything else has been tested out.

Bad RAM:
Run the diagnostic program found at and see if it fails.  Even if it passes, that doesn't mean the RAM is good; only a swap with known, good working RAM will tell you that.

Make sure the speaker is plugged in. Remove RAM modules. If the CPU is running, you'll have violent beeping. No beeps might mean bad CPU or bad power supply.
Was the PC running before you got it? Did you make any changes?
How long ago did it run? How old is the PC?

I would start by reseating all the devices RAM, VIDEO, SOUND, MODEM.

If you have a modem, NIC or Sound Card take them out all together. Reduce any possible problem cards. Then check for activity.
Also can you get anything at all on the monitor? Try another monitor. Can you get into the BIOS? (Save this for last but reset bios to default values. You may want to note all current values before doing this).

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Reset the CMOS by taking the battery out for 10-15sec and then put it back. The problem is most likely either a bad CPU or memory. Disconnect everything except the video card, memory, and CPU and check if it starts correctly. Give some details on the hardware your using like motherboard and video card that your using so E-perts can help you out.


check the video card if it is connected well if not connect it, if problems persist motherboard is the problem i had it before, either the battery in the mb is weak
This is a bad power supply. I just went had this same problem recently. And it was a bad P/S.  The power supply, while it is running, is not supplying the needed voltage to the computer.
Make replacing the P/S your first step. It takes about 15 minutes to replace and P/S from start to finish, the hardest part is hooking up that darn floppy power.

Mark Dozier
I would have to agree with MarkDozier. Power supplies sometimes will continue to work but at a voltage lower than what is required. In fact I've had systems that actually ran but acted speratic and ended up being a bad PS.
Switch out you memory, if got 2 sticks in it. Take out one and leave the other in it, and try booting it, if nothing happens take out memory you left in it and replace it with the one you took out.

I betcha you cooked your CPU....a few of my clients had the same problem..

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