Many notebook won't power due to bad RAM.
But most of the times its a damaged mobo.
I've seen many notebooks with the same problem I even had several of them for parts.
After removing the mobo's and inspecting the PCB I noticed several burn marks.
I have an Toshiba with the same problem, after removing the mobo the circuit around the CPU has many burnned marks.
Once upon a time the floppy disk was king.