HP Pavilion DV4 no power

I was given an HP Pavilion Entertainment PC that has no power. The battery seems to be dead and when I plug in the AC Adapter all I get is the front power light blinking. It will not run from the AC Adapter and when I remove the battery the light on front does not blink. It must have the battery in and the AC Adapter plugged in to have a blinking power light. It tries to start every now and then but only for a few seconds and then shuts down. I have removed the battery and AC Adapter, held the power button down for 30 seconds but results are the same.

Also there is no light where the power supply plugs in, but the light is on on the power supply itself.

Any help will be greatly appreciated...