PC Will Not Boot

Whether you’re a novice or an expert PC technician, we’ve all had an experience when a new PC would not boot. There’s no worse feeling than pushing the power button on the front of a new machine an hearing absolutely nothing. This article will focus on some of the common problems with new builds and help to reduce the computer troubleshooting time when diagnosing problems with your new computer.

Take A Quick Visual Of The Computer

You should have already done this before trying to power up the PC, but a lot of novice PC builders will skip this step in anticipation of powering up their new machine. This step may save you time and money. First, triple check to make sure the CPU is sitting flat on the motherboard socket. It’s probably hard to tell because of the heat sink, but if the entire CPU and heat sink combo looks skewed, then chances are it’s not installed properly. Next, go over the IDE cables and the thin wires running from the power and reset switches to the motherboard. While the IDE cables are keyed, it’s quite possible to get those case wires backwards or completely. Lastly give the PC a little shake. Make sure an errant screw didn’t fall behind the motherboard during the install. This could blow the motherboard or cause the system to go to ground.

Computer Hardware Troubleshooting

When a new PC will not boot, a good place to start is the power supply. Is the machine getting power? If there is no fan activity at the rear of the power supply, then the power supply isn’t working. First, check the wall socket and power strip to make sure power is actually being supplied to the computer. If there is power to the outlet, confirm that the | / O lever in the back is set to |. Then confirm that the voltage is set to 110V in the USA or 220V in countries that require that setting. If you have a voltmeter, you might want to consider testing the power supply. Refer to the pin out chart for the correct power supply voltages.

Troubleshooting Video Cards

If the system powers up, but you get nothing on the screen, the video card may be the culprit. First, confirm the video cable is secured to the video card’s output. If the motherboard has built in video, and you’re using a PCI-E or AGP card, make sure the cable is secured to the correct port. Also, check for bent pins on the connector and confirm the monitor works and the brightness controls are set correctly. Do you hear any beeps? If so, refer to our BIOS beep code chart. It’s always a good idea to reseat the RAM and video card when you get the “No Signal Displayed” message on the monitor.

Dead Motherboard or CPU

Improper installation of the motherboard and CPU can cause instant failure. We like to install the CPU and RAM modules on the motherboard before installing the motherboard in the case this is because it sometimes requires some effort to get the heat sink seated properly on the CPU. The CPU itself should slide effortlessly into place and lock without any problems with the lever. If you require resistance when installing the CPU, make sure the CPU’s pins are properly aligned to the socket on the motherboard. Apply the correct amount of thermal grease or tape as recommended by the manufacturer, then install the heat sink. The heat sink should rest flatly on top of the CPU.

As for the motherboard, refer to the manual about each of the connections to the case. A common problem area are the standoffs between the case and motherboard, and the connection of the thin wires from the power and reset switches to the motherboard.


You will often receive a BIOS beep code when there is a hardware issue with the PC. You should determine the BIOS residing on the motherboard by physically looking for the BIOS chip on the motherboard. Look for something like AMI-BIOS, AWARD BIOS or PHOENIX. Refer to our BIOS Beep Code Chart when diagnosing beep code errors. This will often lead you quickly to the source of the hardware problem.

In Conclusion

While these new computer installations can be frustrating, it’s important to take a step back and think before you do more damage. Take a nap or a walk and then look at the problem with fresh eyes. If you need further assistance, please consult our techs on our message boards.

29 thoughts on “PC Will Not Boot”

  1. Need your help ASAP. My computer stops on the boot screen. Last 2 lines

    256 KB L2 Cache

    Press F2 to enter Setup F12 to One Time Boot Menu

    When I press F12 or F2 nothing happens.


  2. My laptop started making strange “disc” noises. It had been on but idle, I was away from it, and when I came back and touched the touchpad mouse, it made these noises. I emptied my cache, and deleted all cookies. It was running very slow and continuously making low noises. I searched for the disc cleaup file, and started to run that program. I stepped away from it because it takes several minutes to do the initial setup to de-fragment files. I came back and it was on the black “Windows” screen with the “running” icon below. It stays on this screen and will not give me my desktop or any other screen. I turn it off, and the startup black screen gives me the message that it didn’t start successfully and to choose an option below based on how it got shutdown. I choose one of the options (“start windows regularly” or “last good configuration”) and it takes me only to the same black Windows screen w/ the run icon below. Am I screwed?

    1. I’m not sure what you mean by the “run” icon. Sounds like maybe the hard drive is going based on the noises it was making. It’s difficult to say. Do you have backups and recovery disks?

  3. “Running” or thinking or downloading, there is usually a bar that shows you something is happening, in this case that it’s starting up. But it never gets past this screen. The only “backups” I have are discs that I uploaded, like pics and music. So no. And no recovery disks came w/the pc. Someone’s got to be able to start it and/or find out if my files are there and retrieve them, or- I found there are programs to recover all “deleted” or “lost” files. I guess I’ll have to take it somewhere.

  4. Tried to do a factory restore, said could not complete, now when I try to turn on the computer it says press ctrl alt delete to restart, that’s all it does. over and over. what should i do?

    1. What kind of computer is it? Do you have disks. It sounds like it was rnning a Windows update and not it is stuck. Also does it ever shut down? Or does it just say it is going to shut down and hangs?

  5. It is a gateway and we bought it last year..I will check out the model number. It does shut down at times when performing some kind of update. But always will reboot.

  6. I have a DELL and recently it wouldnt load up,,when i checked the pc it said that harddrive could not be found,,,does this mean that the hard drive went out?

    1. It means no hard drive was found. If this is a new installation, check to be sure the IDE cable is correctly connected to the Primary Controller on the motherboard and that the jumper is set to Master on the rear of the drive. You can then check the BIOS to make sure the hard drive is set to AUTO and that the drive even shows up. For extended help, please join our forums.

  7. am working on laptop, the problem is when the laptop is booting the window will stay like 30mins and when it open you can not enter inside the computer , it will bouce back and restart.

    1. Most newer monitors will have a diagnostic screen that comes on when the monitor is on but the PC is not. If the diagnostic doesn’t come up, try the monitor on another computer but it will probably be bad.

    1. Is the computer plugged into a grounded electrical outlet? Is the computer sitting on a rug. This might simply be a case of climate–with this being a cold, dry season. But it could be something more severe, such as a computer that’s not properly grounded.

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