My laptop does not boot up and doesn't turn on. The screen is blank with no power lights on.

[Sandy153]

I have tried all the options available on HP support and nothing works.

My laptop does not start up, no lights lit and the screen is dark with no messages displayed.

After trying numerous options, I decided to plug the adapter in.

After trying many times, pushing the power button down, the computer starts up only with the adapter plugged in.

Even doing it this way, it doesn't always start up.

[WAWood]

@Sandy153 

OK so first of all, I am sure you are not running Window 10 IOT -- so providing us misleading info is not a good way to start.

Second, this sounds clearly like the battery is either dead or the charge to low to power on the PC.

You can check the battery to some extent using Powershell built into Windows 10, as follows:
1) Press Windows key + X
2) Click Powershell in the menu
3) Type powercfg /batteryreport

This will generate a report and if you scroll down, you will see Design Capacity and Full Charge Capacity ratings. If the Full Charge Capacity is less than 50% of the Design Capacity, it is faulty and needs to be replaced.

Also note the figure alongside the "Cycle Count". This tells how many times the battery has been fully recharged. A typical battery can handle around 500 charge cycles, but some will fail sooner than that.