If your computer beeps irregularly when the computer is turned on, or turns on but does not boot, you may be experiencing a problem with the Power On Self Test (POST).
If you are getting a beep code sequence such as one long beep and two short beeps you may want to have a look at our beep code page to see if your beep code is listed there.
Finally, if you reboot the computer several times and it sometimes starts up you may want to read this article - PC restarts many times and then boots up.
Power On Self Test (POST) problems can be caused by any of the following situations.
Before you carry out any work on your computer make sure you protect your PC's delicate circuits from static electric charges on your body by properly grounding yourself. If you don't have a grounding strap at least ground your body by touching the metal part on the outside of your PC's case before touching the inside of your PC or any component, including the motherboard.
If any new hardware has just been added to the computer, remove that hardware to make sure it is not the cause of your problem. If after removing this new hardware your computer works, it's likely the computer is either not compatible with the new hardware or a system setting needs to be changed to work with the new hardware device.
Remove everything from the back of the computer except the power cable. Turn on the computer and see if it beeps normally. If the computer has never beeped also connect a monitor to the computer to see if a message occurs.
If you are receiving a sequence of beeps see our beep code page for a listing of all the different beep codes and what they mean. These beep codes can help you to identify exactly what computer component is failing or is dead.
Make sure all the PC's fans are running. If a fan has failed (especially the heat sink fan for the CPU) your computer could be overheating which can cause it not to boot.
If you were unable to determine by the beep code what component is failing, or do not have a beep code, disconnect the cables from the CD-ROM, DVD-ROM, Hard Drive and Floppy drive and from the Motherboard connectors. If this resolves your irregular POST, attempt to connect each device one at a time to determine which device and or cable is causing the problem.
If our suggestions have not resolved the irregular Power On Self Test (POST), attempt to disconnect the Riser board (if any) and each of the expansion cards (i.e. sound cards, graphic card, modem etc). If this resolves the issue or allows the computer to POST connect one card at a time until you determine which card is causing the issue.
If you continue to to receive the same problem with all the above hardware removed attempt to disconnect the CPU and RAM from the Motherboard. Once done insert the CPU and RAM back into the computer and see if this resolves your issue.
If after doing all of the above you continue to have the same problems it is likely that you have a damaged Motherboard, CPU and or RAM. The next step would be to replace/test these components. At this stage it is often best to have your computer repaired at a local pc repair shop.
