Computer Won’t Start. Power on Button Light Flashing

computer wont bootHow annoying it is when your computer won’t start and you can see the computer power button flashing? One minute they are fine, and the next thing you know it is basically dead. I especially hate it when you press your power button and nothing happens. You can see the computer Power light blinking but nothing comes up on the screen. It seems like the computer is sending me a signal, but what is it trying to say? We have tutorials about computers not starting when the computer has a black screen, when you need to repair the boot sector of your hard drive, and many more. However this article is about your computer not starting, but seeing a flashing light at the same time.

Check the power supply

Unfortunately different makes and models of computers do different things for which could be the same error causing the problem. Some computers have a beep sequence code and others have no signals at all. However when the computer won’t start and the power light flashing on and off I always test the power supply first.

You can also take the side of your computer case off to listen for the cpu fan starting when you press the button. If it seems a bit slow and quiet you can almost guarantee that there is not enough power getting through to your computer. If you have a spare Power supply hanging around and you have done this type of thing before, try swapping them over. If you are not confident in working on computers yourself, get a professional to do it for you.

Computer won’t start and the reasons are too obvious

I was working on a computer with this problem a few years ago, and it turned out to be the power cord. It was faulty, which allowed the computer to work most of the time, but then other times it would not boot and the power light flashed. This was a rare because the problem is usually the actual power supply itself.

If this doesn’t work for you, try removing everything that is connected to your computer. Remove the mouse, keyboard, monitor, PCI cards, graphics cards, etc. Now you should only have the power cable connected. Turn the computer on now. If the blinking power light is gone and it seems to be running, this could mean that there is something wrong with one of the components you have just removed. Replace them one at a time, testing to see if the computer works each time. When the flashing light comes back you know you have found the problem.

If changing the power supply didn’t help, or removing all of the components either, it doesn’t look good. Now it could only be the cpu or the motherboard.

Example problem number one – computer power light blinking

My computer won’t start. I have a Dell Dimension 9150. After a power outage my PC will not turn on. It has a blinking yellow light. Everything I have read said it is most likely a power supply problem. I purchased a new power supply from 911 PC and still have the same problem. There is a green light lit up on the motherboard. Any ideas? I have also read about diagnostic lights to figure out the problem. I don’t believe this PC has any of those lights. Thanks

I did remove the ram and graphic card and tried starting it up without any of that installed and got the same thing. I then put them back and got the same blinking light. The setting is 115 on the power supply although I have toggled it and tried the other setting.
I have also tried just the power supply connected to the MOBO–no drives and get the same blinking light. Two lights also blink on the back of the PC underneath an RJ 45 connection.

Nothing beeps and nothing else turns on. Source.

I did remove and change the memory to different slots and tried starting it up without any memory and got the same blinking light. I received a new power supply and tried it and got the same results. Brought the new power supply to a PC shop and they let me try their tester. It produced lights but it grinded and the fan barely moved. “Possible I got a dud. the place I got the power supply from is great–911 PC . The guy I spoke to on the phone is going to open up and test the new one and initial it before shipping it priority mail–also not even charging me for the new one being shipped as long as I send the old one back. If it turns out the motherboard is shot I’ll send both back and they will refund.

Computer won’t start problem solved

Warning: When working on computers see opening computer cases and please take the right precautions.

Problem fixed. It was the front USB ports that were causing the computer not to power on and the blinking yellow lights. I took a screwdriver and kept messing with the pins on the beat up port–pushing them down, spreading them apart, etc. etc.. until finally no lights on power button. I then pushed the power button and it started right up. That port for sure is fried but I don’t care. The computer works.

Thanks for the help! I had this exact same issue to the Tee with a Dell XPS 400. The front USB pins were touching causing a short on the motherboard. After i stuck a screw driver in there and pulled back the pins just mike magic everything started working!

Eg problem number two – computer power light blinking

Solution From Lloyd

Lloyd February 25, 2012 at 9:53 pm

It is not always a power supply problem – as in the power supply needs to be replaced. It has something to do with leftover energy that needs to be discharged. A hair dryer blowing in onto the tower’s fan will cause it to run in reverse negatively discharging the built up or leftover energy  It doesn’t seem to work with cold air but also needs the heat. Don’t put dryer up against the casing, don’t want to cook the fan motor! :) Anywhere from 30 seconds to 2 minutes should cause light to go solid. Then you can start computer in normal mode. This method has worked 2X on my SR5601P.

Marnie February 16, 2013 at 11:57 pm

My dell computer wouldn’t start, and had the blinking green light. Checked the power source (cord), plugged directly into wall, open cpu unplugged all connections, took out ram, replugged in all connections, put ram back in, made …sure all connections in firmly(if ram not clicked in snug- will not work). Then checked cables going into power button to see if any disconnection, also looked at motherboard to see if anything disconnected. Checked usb ports to see if any pins bent (which can cause a short)…… These are all the first steps to try to get computer to come back on. Nothing worked.—- SO THEN I TOOK A HAIR DRYER TO CPU FAN AT BACK, RAN IT FOR ABOUT 1 MIN, 30 SECONDS AND …….. UNBELIEVABLY THE GREEN LIGHT WAS SOLID, AND MY COMPUTER IS WORKING FINE…. Totally amazing””” It really works. Thanks

More examples in comment section.

Quick troubleshooting tips

If your computer won’t start and you have a flashing power light then you can try the following:

  1. The first thing you should do is check to see if you have valid warranty on your computer. If you have then you should get it repaired by the appropriate person or you will void your warranty.
  2. If you are plugged into a surge protector or UPS, try plugging it straight into the wall. If killing the power for a few minutes doesn’t do the trick, it sounds like a hardware failure. Could be faulty power supply, or mainboard as the first possible culprit. I would suggest getting it looked at by a competent technician.
  3. Have you tried changing the power cord over.
  4. Try a hard restart by pressing in the power button until the computer shuts down. Under plug all the power cables, the power button while the computer is unplugged, then plug it all in again and try to restart it.
  5. Check inside the computer case and make sure the power cables are connected securely. There could be a loose connection that is causing this problem.
  6. Try a new power supply.
  7. Check connections on your motherboard, for example the pins, disconnected cables. Bent pins cause power shorts.
  8. You can check your RAM, but I have never seen an amber flashing light, and found that RAM was the problem. But there is always a first!

http://support.dell.com/support/edocs/systems/dim5100/en/sm/tshoot0.htm

What does the blinking light on the computer mean?

If you have a Dell computer, here is a table showing what lights mean what. For example if your computer won’t start and you see a solid amber light this can mean that either the system board is faulty or the devices connected to it.

Your power button light and hard-drive activity light may indicate a computer problem. This table was transferred from a Dell manual. If you have another brand of computer, try looking through the repair manual to see if you can find something similar.

Power Light Solid Green: Power is on, and the computer is operating normally. There is no corrective action as the computer should be working.

Power Light Blinking Green: Power is on, and the computer is operating normally. Press the power button, move the mouse, or press a key on the keyboard to wake the computer.

Power Light Blinks Green several times and then turns off: A configuration error exists. Check the diagnostic lights to see if the specific problem is identified.

Power Light Solid Amber: The Dell Diagnostics is running a test, or a device on the system board may be faulty or incorrectly installed. If the Dell Diagnostics is running, allow the testing to complete.Check the diagnostic lights to see if the specific problem is identified.If the computer does not boot, contact Dell for technical assistance (see your computer Owner’s Manual for information about how to contact Dell).

Power Light Blinking Amber: A power supply or system board failure has occurred. Check the diagnostic lights to see if the specific problem is identified. Also, see “Power Problems” in your computer Owner’s Manual.

Solid green and a beep code during POST: A problem was detected while the BIOS was executing. See “Beep Codes” for instructions on diagnosing the beep code. Also, check the diagnostic lights to see if the specific problem is identified.

Solid green power light and no beep code and no video during POST: The monitor or the graphics card may be faulty or incorrectly installed. Check the diagnostic lights to see if the specific problem is identified. See “Video and Power Problems” in your computer Owner’s Manual.

Solid green power light and no beep code but the computer locks up during POST: An integrated system board device may be faulty. Check the diagnostic lights to see if the specific problem is identified. If the problem is not identified, contact Dell for technical assistance. See your computer Owner’s Manual for information on how to contact Dell.

Hard-Drive Activity Light Solid green: The hard-drive activity light is on when the computer reads data from or writes data to the hard drive. The light might also be on when a device such as a CD player is operating. No corrective action is required.

  • One other idea is to try changing the bios battery.. You never know..LOL

Have you got any tips for us to try when the computer won’t start and there is a flashing power light?

Comments

  1. Marnie says

    My dell computer wouldn’t start, and had the blinking green light. Checked the power source (cord), plugged directly into wall, open cpu unplugged all connections, took out ram, replugged in all connections, put ram back in, made …sure all connections in firmly(if ram not clicked in snug- will not work). Then checked cables going into power button to see if any disconnection, also looked at motherboard to see if anything disconnected. Checked usb ports to see if any pins bent (which can cause a short)…… These are all the first steps to try to get computer to come back on. Nothing worked.—- SO THEN I TOOK A HAIR DRYER TO CPU FAN AT BACK, RAN IT FOR ABOUT 1 MIN, 30 SECONDS AND …….. UNBELIEVABLY THE GREEN LIGHT WAS SOLID, AND MY COMPUTER IS WORKING FINE…. Totally amazing””” It really works. Thanks

  2. Shruti says

    Thanks for the tips. But I have some strange problem regarding this. I suffered from save problem of fault light and contacted to an hardware specialist. Now the problem is resolved but one more problem that has been generated. That is when I start my CPU, t starts normally but while doing work, automatically it gets off and again fault light starts. Do you have any Idea about it.

  3. Les says

    Mitz – I have read your article on “Blinking Power Light” and there are some good tips for me to try out. I have an em/c computer with this problem – the only differenc as I see it is that as soon as I plug in the cpu fan starts up and of course the light starts flashing. I think I am beginning to suspect the power supply or could it be that there seems to be so much “dust”inside the case causing the problem. Anyway thanks for the tips and keep up the good work.

  4. Finger says

    I was having the same problem..
    It took me several hours to find a solution but the solution is easy
    I just replaced the RAM in an other slot and then it worked well,,
    Now im thinking that what if i had dont this some time b4

  5. Benedict Lee says

    Hi. When i press the power button on my computer, nothing happens. No lights blink and no beep. I have checked all the connections, and the power supply seems to be working fine as well as the activity indicator on my modem shows my PC PSU is ok. Could someone please assist me with this issue? Thank you.

  6. Sara Garner says

    I have a RCA LCD TV (model # 32LA30RQ) and a Dell Dimension 3000 PC. I don’t have the model number on the PC because part of the sticker is missing. What kind of cable do I need to connect them? Will I need a separate audio cable? I was on the Dell website and there was no mention of the cable so any help would be much appreciated.

  7. Lloyd says

    It is not always a power supply problem – as in the power supply needs to be replaced. It has something to do with leftover energy that needs to be discharged. A hair dryer blowing in onto the tower’s fan will cause it to run in reverse negatively discharging the built up or leftover engergy. It doesn’t seem to work with cold air but also needs the heat. Don’t put dryer up against the casing, don’t want to cook the fan motor! :) Anywhere from 30 seconds to 2 minutes should cause light to go solid. Then you can start computer in normal mode. This method has worked 2X on my SR5601P.

    • David says

      Lloyd, the Olympics are in full swing here in the UK, and if I had a Gold Medal to award, I would give it to you. Your hair dryer technique has just rescued the HP Pavilion that I was about to scrap, or to start expensive component replacements. A green light that was flashing irritably at me has now stabilized into a steady green smile! Thank you for this simple method. I now have my favourite PC up and running.

      • Deb Lahey says

        I have a dell inspire about 12 yr old lap top, I accidently spilled liquied on it, uplugged it wiped it ,upside down it and left for 2 days, the battery icon light flashed green then red, and it is not loading at least screen stays black, have I lost my lap top and info on hard drive.
        I thank you in advance for any advice.
        Deb

    • Sandra says

      Lloyd
      OMG OOOOHHH MY God it worked !!!!!!!!! First I did it with the computer off and it didnt work so I turned it on and nothing happened. So I turned computer off and back on and I saw my screen light up. OMG what do you do that you know this stuff. Never mind I dont care all I can say is Thank You, Thank You, Thank You.

    • tmcmski says

      WOW! I was really skeptical, but willing to try anything to save the information on my computer – I had been getting some strange-looking safe mode (really crazy colors, low resolution, etc) and thought it would die any die and sure enough, the next day, I couldn’t get the Dell Dimension 9100 to power up. Used the fan on it and it started and now I’m going to back it up before it’s totally gone! Thanks

    • Alex says

      What the heck???? It worked! I have a Sony Vaio that I bought in 2004 and I thought that this just may have been an end of life issue. I used the hair dryer and it worked like a charm. INCREDIBLE! Thanks, from me and my wallet.

    • Scott says

      WOW, WOW, WOW!!! That’s all I can say! Llyod, you are a life saver! Thought my HP was toast. Thought I tried everything. I figured best case, it was going to need a new power supply, worst case, it was going to be thrown out the window. As a last restort, I tried your hair dryer technique, and to my astonishment, the green light when from blinking to steady on within 30 seconds of blowing hot air into the fan from the back. Problem solved, and my computer is up and running again. Glad to know there are people like you out there to help those of us less fortunate with computer skills. Thanks again!!!

  8. Rathnaiah says

    when I pressing the starting button of my computor blinking the mouse only but not catching the power and not starting the system. please anyone solve my problem

    • Mitz says

      hi there…
      we can try a few things here…
      **The first one is to hit CTRL ALT DEL to bring up the task manager To start explorer.exe. You click on the button to start a new task and then type explorer.exe
      this should bring back your desktop. If this does not work then it could be a display problem. Please let me know if you can do this.

  9. Dara says

    I had the same problem and replaced the power supply, and the computer is up and running happily now.

    Thank you!