Hi,
Here's some troubleshooting steps that may help in solving the issue.
- Start by doing a hard reset, unplug the AC adapter then press and hold the power button for 20 seconds and see if it will boot up.
- Next, if it won't boot up is to reseat the RAM, remove them all for couple seconds the n put them back in making sure that they are seated properly into each slot.
- Also test the HDD, remove it from your laptop then boot it up and see if it load to a black screen with an error.
- Put the HDD back in and see if it will load up.