Please do try these troubleshooting steps that may help in resolving the issue.
If there are lights on the laptop (HDD, Wifi...)
- Do a hard reset, remove the battery and AC adapter then press and hold the power button for 20 seconds. Plug just the AC adapter then try to boot the laptop, if it loads to the desktop you can put the battery back in.
- If there are lights on the laptop try and connect an external monitor and see if you'll get any display from it and if you don't that means it could be a motherboard failure.
If there are no lights what so ever on the laptop.
- Start by testing the AC adapter using a multi tester if it's supplying enough voltage to power the laptop or try another AC adapter. If it works with another AC adapter you have your culprit.
- If there's light on the AC adapter but nothing on the laptop it may be an issue with the motherboard still.
- Do contact Lenovo Support if it's still under the factory warranty for a repair.