Computer won't POST after power outage

Question

I had just turned my computer on and windows was loading when the power in my neighborhood went out.

• Normally, when I turn my computer on, the video card fan spins up, then slows down, POST and windows boots.

• Now, after the blackout, the video card fan spins fast and wont stop. Nothing is displayed on the monitor. The monitor does not detect that the video card is sending it signals, it just stays on standby. No POST or beep codes.

This is what I have tried so far:

• My motherboard has 2 PCI express slots and I tried plugging the video card into both of them but that didn't fix anything.
• I have replaced the power supply, that didn't fix anything.
• I cleared the CMOS, that didn't fix anything.

Does anyone have any idea of what could be wrong?

Solution 1

A motherboard that shows the symptoms you are describing requires some serious debug. The fan spinning at full speed and lack of POST or beep codes tells me that BIOS isn't loading.

• Strip the motherboard down to the bare essentials: Processor, 1 stick of memory, video card and of course, power (it might be easier to do this if the motherboard is outside the chassis).
• Do the correct LEDs come on when you power up the board?
• Do you see the board POST when you:
  • Swap out the processor?
  • Swap out the video card?
  • Swap out the memory?
  • Swap out the BIOS ROM chip with another programmed one?

If you have a PORT 80 card that will plug into your motherboard or it has PORT 80 LEDs onboard see what POST code is displayed. You can tell where BIOS is failing by comparing the HEX digits to the BIOS vendor's POST decoder. POST 00h or FFh usually means the BIOS isn't loading.

If you can't get it to POST this way and you aren't into electronics, then you're pretty much done. Try your parts on another motherboard and see what you can salvage.

Solution 2

Reseat the RAM. It may have come loose, especially as you were replacing the power supply. Reseat all add-in cards.

Unplug USB, Firewire, etc. devices.

If you have another video card, try that. Or try w/o any video card (though some boards will not POST w/o video)

Try with peripherals unconnected: pull the connectors from the hard drives, optical drives, etc.

If it still won't post, you're probably looking at replacing the motherboard.

(Did you have a surge suppressor?)

Solution 3

Try to replace the battery on the motherboard. That should allow your computer to work again and boot to your OS.

Solution 4

Recently answered a related question
What damage will powering down instead of shutting down do?

Do you have on-board graphics?
Unplugging the graphics card would let you identify it the card is causing a problem or the POST is hung in some way. Its supposed to BEEP in specific sequences on failures usually.

In fact, if you do not have on-board graphics, I'd still suggest you unplug the card and check for a boot.

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Comments

[user12889]

Did you try to contact the Motherboard manufacturer for help?

[hade]

So, the Video Card fan not spinning down would mean that it didn't pass the POST and no beep codes say BIOS isn't loading? I would do all of the things you mentioned except...I don't have any spare parts. The only thing I had was a spare PSU and that didn't solve the problem. I am pretty much ready to buy a new Mobo, RAM, and CPU, I just wanted to know what you guys think.

[hade]

I don't have any on board graphics. I tried to boot without the video card but it still doesn't give any beep codes.

[hade]

I tries reseating the RAM and trying each stick individually one by one and that did'nt fix the problem. I tried booting without a videocard and it didn't even give me any beep codes. I also tried booting with just the RAM and CPU in on the Mobo but nothing. I have a surge suppressor, but im pretty sure the fuse had already been blow (yes i know, stupid me). I learned my lesson.

[hanleyp]

On desktop boards, the BIOS or an ASIC will setup the fan control (fan throttling based on temperature) otherwise, the fan will run at full speed. BIOS could still be loading, but hanging before the fan control. Not sure what motherboard you have, but no beep codes also could mean the board doesn't have an annoying beep speaker installed or the BIOS doesn't support beep codes.