many people search on google and ask on Quora  about the laptop  power on but screen is blank .it is  most common issue in laptop  there is many reason  to occur this types of problem, i am  going to share short  process to check this types of issue.

       first you have to remove the battery wait for few seconds connect power adapter and  turn power on the laptop,  if problem not solved remove any external devices connected to USB port some times  USB devices also short and laptop power on and screen is blank, remove HDD,DVD and see,  most of times we find RAM faulty  so please check RAM also. if problem not solved  after changing the RAM  may be laptop mother board is problematic in this case you have to send your laptop to laptop repair center. Don't try anything out of your skill it is cause to permanently  dead your laptop. some times there is dim display in this case check  LED/LCD and  VGA cable  if both are ok  may be problem in laptop motherboard.

         in laptop motherboard power regulators, power chip ,chip set , bios  and many types of component like coil,capacitor ,transistor, diode ,ic, FET,   etc, if any one of them faulty  laptop screen is blank .After proper diagnosis engineer will find the faulty component  and  replace with new one then problem will be solved.