For overcoming the problem of the hanging up of the display when the power button is turned on, I will proceed with the following steps

:• Turn off the power button and open the caching, remove carefully the data cables and power cables connected to the hard disc, CDROM, and after reconnecting the cables, I will restart the computer;

• If the problem persists I will check RAM, processor, power supply connection separately whether they are faulty or loosely connected;

• If the problem still persists, set the motherboard with a sound computer, run and check whether it is active or not;

• If it is not active, change the motherboard. get the job done by an expert hand taking the computer to a service center;

• It is worth mentioning that sometimes this problem persists when the keyboard and the mouse port of the motherboard are loosely connected. If it is so,  set the connection properly.