Hey guys! So my dad has an HP Pavilion DV9700 and one day he told me that it wont start up so i took a look at it and i cant see to figure it out. It is not the battery because i can charge it and then turn it on only to find that it stays on with no video feedback for literally 1 second after the power button is pressed. I have tried it without the battery, removed and replaced the ram and HDD etc. When It turns on for that 1 second, all lights come on at first except for the light on the mouse pad border and the laptop shuts off when the light on the mouse pad boarder comes on. Thanks in Advance!
Do a hard reset first, remove the batter and AC adapter then press and hold the power button for 20 seconds. Plug just the AC adapter in and see if it turns on. If still won't power on connect an external monitor and see if you'll get any display from it because if you do there might be an issue either with the flex cable or the actual display of your laptop.