Please do try these troubleshooting steps that may help.
- First is to do a hard reboot, remove the battery and unplug the AC adapter then press and hold the power button for 20 seconds and see if it will boot up normally.
- If it will still not work, connect an external monitor and see if the same problem will persist on it.
- If it will still not boot up, proceed with reseating the RAM's. Remove them all for couple of seconds then put them back in making sure it's seated properly.
- And if it will still not boot up try loading it in Safe Mode. While the laptop is booting up repeatedly press on F8 until it loads Advanced Boot Options then select Safe Mode.
- If Safe Mode will still not load and will result to the same problem. Last option would be to reinstall Windows.
- If all these will not work, do also try a different AC adapter that has the same voltage and see if it will still not work.