Are there any lights on the laptop other the battery or charger indicator? If there is non it could be a hardware problem (Motherboard) but if there is there might still some ways to bring it back to life.
- Remove the battery and AC adapter then press and hold the power button for 20 seconds. Plug just the AC adapter and see if it boots up normally then you can put the battery back in as well.
- Reseat the RAM, take them of for couple of seconds and when you put them back in make sure all them are seated properly in each slots.
- Connect an external monitor and see if you'll get any display from it because if you do possible that the built in display has gone bad.