Hi,
Please do try these troubleshooting steps that may help.
- Start with a hard reboot, remove the battery and unplug its AC adapter then press and hold the power button for 20 seconds then try booting it up again.
- If it will not boot up do reseat the RAM's, remove all the RAM's off then put them back in making sure everything is seated properly into each RAM slot.
- If all these will not work try to reset the CMOS battery. Once you've opened the back of your laptop the CMOS battery should just be on the upper left part of the laptop battery and on the right side of the HDD. You don't have to remove the whole CMOS battery because it has a cable that's connected to the motherboard (black and red cable).
- After the reset do try it again and see if it will boot up.
- If it will not boot up try also booting the laptop without its battery or also do try a different AC adapter that has the same voltage.
- If all these will not work contact Lenovo for a repair if it's still under the factory warranty.