I'm building a custom computer with the following specifications:

When I attempt to boot it for the first time, the GPU and AIO Cooler lights turn on, as does the case's power indicator. The fans spin as well. However, my monitor does not show any output at all, and it does not POST. As well, it intermittently turns itself off and back on every ~5 seconds.

My attempt at troubleshooting included the following steps:

  • Checking the CPU for any bent pins
  • Removing the motherboard's battery
  • 'Breadboarding' (removing SSD, then memory, then GPU)

As well, while building, I placed the parts and case on a static discharge mat, as well as wore a static discharge wrist strap.

Any suggestions are greatly appreciated, thanks!


Something very basic is not working (duh!) Since it's not POSTing, there's a problem with the MB, RAM, CPU or PSU. The HDD & GPU are irrelevant. Cycling on and off every 5 minutes sounds like it could be an overheating problem. Does the CPU heat sink have just a little paste on it, and is it firmly seated on the CPU? If it isn't, the CPU will overheat in less than a second and shut itself off. As others have said, make sure everything's seated firmly (RAM) and swap out parts one at a time.


I would:

  1. Go into BIOS and have a look round for anything suspicious and reset to defaults.
  2. Re seat all your hardware/cards.
  3. Check all your motherboard connections.
  4. Make sure you have seated your RAM in the correct slots.

If that doesn't work I would suspect a faulty part. Sorry if this is all obvious for you.

  • How do I go into the BIOS since it won't even POST? Other than that, I did all the other steps to no avail. Mar 24 '19 at 3:47
  • On my motherboard I have to hit the del or F2 button as soon as I switch on the PC. It may be different on yours but it normally tells you on the screen or in your manual. POST starts after your opportunity to enter BIOS has passed. Mar 25 '19 at 7:46
  • @BanjoDaHousecat - The author's machine does not even remain on longer than 5 seconds. Indicating they should restore the default firmware settings, does not address their more immediate problem, the machine does not POST.
    – Ramhound
    Mar 25 '19 at 14:01

The BIOS is the system that initializes most of the hardware on a computer . The GPU is for images and videos.It just fills the frame buffer with an icon ,which is part of the RAM(frame buffer) Check if your memory has enough memory for screen buffer(part of memory which contains data about the reperesantation of the content on display).The CPU has nothing to do with your problem

  • How do I got about doing all of these steps? Mar 24 '19 at 3:47
  • I would check if my components of the hardware work correctly.Does the monitor works fine if you dont use it as an output for your computer?Then I would check my BIOS .BIOS also tests if the hardware components work correctly.Have you checked the datasheet of the motherboard to see its architecture?
    – Altair
    Mar 24 '19 at 9:53
  • I am not entirely sure how you can rule out the CPU in a case like this. The machine does not POST. The machine should be able to POST without a GPU. A faulty CPU would be one of the few things that would explain the behavior the author describes.
    – Ramhound
    Mar 25 '19 at 14:04
  • The machine wont post if there isnt enough space in memory for the screen buffer.Screen buffer is a part of computer memory which is used by a computer application for the representation of the content to be displayed.CPU is just a circuit which performs arithmetical,logical , controlling and I/O operations based on instructions by a computer program.
    – Altair
    Mar 26 '19 at 8:08

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