How do i repair my compaq laptop it those no turn on

When you connect the power adapter into the laptop, does the power LED light up? If not then - The battery adapter or the adapter's power lead or the laptop's power socket could be faulty. Check power adapter's DC plug that connects into the laptop power socket with a multi-meter, the voltage should be slightly higher than the voltage that is printed on the label on the bottom of the adapter. If the voltage is zero or way below the voltage that is printed on the label then the power adapter is faulty and needs to be replaced. If the adapter is OK then connect it to the laptop and power it up, then look at the power/battery charging LED light and wriggle the power plug in the laptop's power socket. If the power/battery LED light flashes and in a certain position this LED light stays firm, then the power socket is either faulty or it has a dry solder joint where it is connected to the motherboard. This can be repaired but it requires the laptop to be completely dismantled to get at this power socket and repair. If you cannot DIY then I suggest you get a quote first.