Hi,
Do a hard reset first with it, remove the battery and AC adapter then press and hold the power button for 20 seconds. Put everything back together and see if it turns on with no problem. Normally the PC might just went into a Hibernate mode when it was not used and won't turn on unless you do a hard reset. If that doesn't work try connecting an external monitor and see if you'll get any display because if you do you might need to open the laptop and see if there's something wrong with the cable of the actual display.