Hi,
Please do try these troubleshooting steps that may do the trick.
- Start by doing a hard reset, remove the battery and AC adapter then press and hold the power button for 20 seconds and see if it will boot up and stay on.
- Next to test if your AC adapter, remove the battery and just boot the laptop with just the AC adapter see if it will stay on.
- If these will not work try to reseat the RAM, remove them all for couple of seconds then put them back in making sure that they are seated properly.
- Lastly is to clean the inside of your laptop and make sure to apply a new thermal paste on both the GPU and CPU that should help in cooling the laptop.