Hi,
Please try the following troubleshooting steps:
■ Start with a Hard Reboot
Remove the battery and unplug it's AC adapter then press and hold the power button for 20 seconds then try booting it.
■ Change your Power Source
Try to boot your laptop without its battery and just use its AC adapter as a power source.
■ Re-seat the RAM
If the above did not resolve your issue, please re-seat the RAM. Remove the RAM sticks for a couple of seconds then re-insert them, making sure everything is seated properly.
■ Connect to an External Display
If you can hear the laptop is on, but there is no graphics on the display, please connect your laptop to an external monitor and see if it will display anything. If the external monitor displays your laptop's graphics your laptop screen may be faulty.
■ Test another AC Adapter
See if your AC adapter is working properly. You can test this by trying another AC adapter that has the same voltage.
■ Service and Repair
If none of the above works it could be a motherboard problem. At this point I would recommend to bring your laptop in for service and repair.