My computer won't turn on (with a little twist...)

By BASSplayerACE · 18 replies
Nov 9, 2005
  1. Ok, so I'm sure some of you have heard this problem a million times, but here it goes...

    After a power outage, my PC will no longer turn on. I replaced the PSU and it still will not work. When I plug in and turn on the new PSU, the LED's light up in the case, and the fans spin for a split second. Ok, so far, this is the run-of-the-mill problem, but I noticed one thing strange...dun dun dun:

    there are two LED's on the mobo. one flashes when I turn the PSU on. The other one, (that just happens to be located near the connector on the mobo from the PSU) DOES NOT EVEN BLINK when the PSU is switched on. This may be a dumb coincedence, but does that mean something is wrong with the mobo?

    By the way, I've already tried the possible solutions that I found in various forums such as trying a differant outlet, checking the CPU fan (dont know how this one would help...), and making sure the power button wire was connected to the mobo.

    Any help is appreciated!
  2. poertner_1274

    poertner_1274 secroF laicepS topShceT Posts: 4,172

    Have you looked at the mobo for blown capacitors? They will look bloated and have a rounded top, instead of a flat top. There might even be some crap oozing out of them. I have had this happen twice after a really bad brownout that fried my UPS, as well as my mobo and PSU. That could very well be why some of those light aren't coming on.

    :wave:Welcome to TechSpot:wave:
  3. BASSplayerACE

    BASSplayerACE TS Rookie Topic Starter

    hey thanks! umm, i believe the capacitors are the cylinder shaped things that have a plastic shell? if so, they all seem to have flat tops and not misshaped.

    thanks again!
  4. patio

    patio TS Guru Posts: 482

    Try removing the CMOS battery for a few minutes...this will reset the BIOS back to the system defaults.

    patio. :cool:
  5. Sharam

    Sharam TS Rookie Posts: 509

    Power failures do strange things at times; basically it comes down to how many blows your power supply and in turn other components have already absorbed in the past.

    For instance, if any of your ATA or optical drives is dead, you will not get through POST.

    Try re moving all cables and power connectors except your CPU fan, also remove all your add-in cards, you want to try and see if the system boots with the CPU, RAM, Video card and keyboard (just in case)

    If you get something add components one by one there after.

    If you don't get anything try connecting your floppy drive and see if it is being accessed (light going on during boot) sign of corrupt BIOS image file.

    After accidents like this, I like to disassemble the system and re build it, I don't know if you are up to that.

    Of course try these after trying what patio has suggested.

    Let us know
  6. BASSplayerACE

    BASSplayerACE TS Rookie Topic Starter

    As far as the CMOS battery goes, Im not sure where it is/how to remove it. It has been a while since I've built the computer, and in that time, I've forgotten most of the mobo parts. :confused: Also, is it possible that the CMOS is just straight-up dead and needs to be replaced?

    btw, would this actually be causing my computer to not turn on? I thought I might be a capacitor like what was previously suggested, but they dont look deformed. Is it possible to have a bad capacitor that is not deformed?

    As far as disconecting ATA devices, did that already and didn't help, and the only other card i have is the modem, which i dont even use anymore! lol...

    I dont have a floppy

    I will try to break the system down to the basics again, but it wont be till tonight, as im at work right now...haha. ugh...hope i dont gotta buy a new mobo, cuz i have a socket A CPU, and those are antiques now! lol (AMD Athlon XP 2500+)

    anyways, thanks for helping me out with your suggestions! much appreciated
  7. BASSplayerACE

    BASSplayerACE TS Rookie Topic Starter

    Ok, so I've tried taking the CMOS chip out, and that didn't do anything. How can I tell if the CMOS is bad or not?
  8. Sharam

    Sharam TS Rookie Posts: 509

    You took the actual chip out, ouch!

    It is not the chip most time but what is in the data block of the chip, if you bent any legs or if you insert it the wrong way then, sure, your chip is bad. But the data could be flashed on it over and over again. Most motherboards have a battery that is clearly visible, some, mainly older laptops, use a capacitor to store information and older motherboards use other types, yours should be coin Cell like in this picture but at 3.3V

    Let's stop fishing, can you tell us what motherboard you have?
  9. Sharam

    Sharam TS Rookie Posts: 509

    Forgot to say, before you re insert the chip, remove the battery :knock:
  10. BASSplayerACE

    BASSplayerACE TS Rookie Topic Starter

    i meant to say the CMOS battery, not the chip. I took the battery out and replaced it after a few minutes. That is what did not work. could it be that the battery is just dead? How would I check, and if it is dead, where would I get a new one?

    btw, i have and XFX NF24-ALH mobo
  11. Sharam

    Sharam TS Rookie Posts: 509

    Your system should and will boot with or without the battery. All the battery does keeps date and time as well as your basic hardware configuration. It will detect your hardware upon POST any way. But with a dead battery you will have to re set your CMOS values according to your configuration and preference every time you power on. That’s all.

    Sometimes with power failure you just loose your power supply, sometimes other components. We have to check each and every component in your system, may be all that is wrong is a dead video card!!? Are you sure your monitor is OK? That light that is not ON on the motherboard, was it on before or is it the warning light for the AGP, some motherboards have that light to ensure you use a compatible card. And Heat sink fan is important since you asked, some motherboards will not power up if they don’t sense the fan’s RPM. I’m not saying this is your case.

    Do you have another system so you can test your components in? Do you have other old components you can try? Even a PCI video card

    I would take the motherboard out, examine it visually, add a known working memory, add a known working CPU with the heat sink and the fan. Add a known working video card and connect it to a working monitor, if with this setup you can not power up, then we can say for certain, it is your motherboard. But hopefully it is one or 2 components. You can have the battery out while you remove the motherboard and all, some, leave it over night. I know it is a pain, but it could be a learning process as well or it will be an invoice from your friendly local computer shop.

    I’ll locate your motherboards manual and look through it since you provided model, thank you for that.
  12. Sharam

    Sharam TS Rookie Posts: 509

    You can check your battery with a volt meter, top is positive bottom negative, should read 3.3V.
  13. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,345   +11

    Have you tried that the PSU works, BASSplayerACE?

    ATX PSUs can be powered on without a mainboard, too, you could check if it spins up hdds, for example.

    Just connect the green wire to any black on the mainboard power connector.
  14. kirock

    kirock TS Rookie Posts: 1,221

    His mobo's dead. If he replaced the PSU, I have to guess it's working, all things not needed have disconnected and still no POST, that leaves...mobo. Buy a new PC. (i.e. you said yourself, the CPU is old etc.) maybe time for a complete upgrade.

    Cheers and good luck.
  15. BASSplayerACE

    BASSplayerACE TS Rookie Topic Starter

    In reply to Sharam:

    -the led that is not even blinking when the PSU is switched on used to light up normally.
    -im at college, so I have no other computers with me or components
    -the heatsink fan starts to spin when the PSU is switched on.

    and in response to kirock:

    -lol, i'd love to get a new PC, but like i said above, im a college student will hardly any money and planning to get married in the not too distant
    - how sure are you (short of having the pc in front of you) that it is the mobo? if thats the case, then just a new mobo fits my budget a little better.

    btw, what do you all think of this mobo?

  16. kirock

    kirock TS Rookie Posts: 1,221

    Well, I'm not 100% sure it's the mobo, but even with a dead CPU it should be able get into the BIOS. If you remove the RAM you should get beeps from the mobo. You might try removing both(any electronic device can fail in such away as to be a short to ground, this would "pull" your PSU voltage below minimums). See if you at least get beeps. If not your mobo's dead.
  17. Sharam

    Sharam TS Rookie Posts: 509

    I never knew this nor have I ever experienced it ...
    Things that make you go ... hmmmmm
  18. Akito

    Akito TS Rookie

    I found this thread while google'ing my own problem, that was pretty much the same as this one. And after solving my problem, i guessed that my experience could help the next person the finds this thread.

    My computer would not turn on, but i could see the fans start and stop again for a second. My first guess was the psu, then the ram, then the mainboard.

    After having swapped everything, i found out that it was the graphics card that caused my computer to not boot properly. A almost brand new Sapphire ATI Radeon X1650 512MB AGP.

    So i guess there is a short-circuit in the card that makes the computer not start. But i do know the computer starts without the card.
  19. pdyckman@comcas

    pdyckman@comcas TS Rookie Posts: 527

    The 20 or 24 wire loom that plugs into your motherboard sometimes will get to where it needs to be twisted a little at the connector at the board. If you have a new PSU but it's not going on, I think that your board may have a short (hopefully at that connector). As you are pushing in the power switch to turn it on, wiggle those wires and watch for your fans to spin, or at least jump in an effort to begin spinning. If you get some action there, mess with that connector. Pull it out a little and try it, (stuff like that). It's worth a try and won't hurt anything. It may be that the power outage has nothing to do with your problem.
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