Troubleshooting System - No POST

Sometimes your computer may power up but would not show you anything on the monitor. Every system performs what's called a Power On Self Test (POST) when it's first turned on. If this POST even doesn't occur, then there's a potential problem within the system preventing it from completing. In this guide, you will find out how to troubleshoot POST-related problems.
Possible Issues
If the system refuses to POST or display anything on the screen, there can be quite a few issues that can cause this. Depending on the parts you have available, you might not be able to test the system fully, but there are few things you can do without any parts to try and isolate the issue.
  • Incompatible BIOS settings
  • Defective part(s)
  • Wrong configuration

Incompatible BIOS Settings

If the system is refusing to POST because of issues with the BIOS settings, for example they were changed or corrupted, then the best thing to do is reset the settings by clearing CMOS.
Some motherboards have an easily accessible CLEAR CMOS button on the back panel with all the I/O ports. Others don't have this button, but rather a set of pins with a jumper on the actual board.
In either case, please refer to the motherboard manual for instructions on how to clear CMOS on your particular model.
Defective part(s)
Almost every unit in a system can cause it not to POST if there's some kind of an issue with it.
Best thing to do when a system wont POST is to disconnect all peripherals that are not required for a normal POST. This includes:
  • Optical Drives
  • Hard Drives
  • Expansion Cards
  • Card Readers
  • External Drives
  • Other devices

If the system continues to fail to POST, you may try to boot with only 1 stick of memory. You can also try swapping sticks of memory and see if the system POSTs then.

If you have an onboard video, try connecting your monitor cable to that port and remove your graphics card entirely.
If the system still does not post, then most likely there's an issue with either:
  • Motherboard
  • Processor
  • Power Supply

In terms of frequency, the failure is most likely to occur with the motherboard, while the least likely to fail is the processor.

*Disclaimer: AVADirect and its Staff are not responsible for any damage to software/hardware, loss of data or personal injury by following our How-To guides. These guides are provided only as an aid to help you troubleshoot system problems. If you do not feel comfortable performing these steps its always best to send in your system to a local repair shop or contact an appropriate technical support line for additional assistance.