Here are some troubleshooting steps that may help.
- 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.
- Next is to try to boot your laptop without its battery and just use its AC adapter.
- If this doesn't work re-seat the RAM. Remove the RAM sticks for a couple of seconds then re-insert them, making sure everything is seated properly.
- If this does not work and you can hear the laptop is on, but there is no graphics on the display, 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.
- If it does turn back on proceed with reinstalling Windows 8.
- The next thing to try is to see if your AC adapter is working properly. You can test this by trying another AC adapter that has the same voltage.
- If all these will not work it could be a motherboard problem. At this point I would recommend to bring your laptop in for service and repair.