Wont turn on but getting power

I have an older laptop, Gateway NV5813H. Great machine. Running Vista.

While plugged in, the battery indicator light is on lit up blue. Adaptor light is on as well.

The power button had some trouble before but it would finally kick on. Now nothing is happening. Just want to get it running for my son to watch youtube.

Any ideas ?

I already took it apart and checked the connections.