If the SMC reset as linked above doesn't work for you, try the following...
Make sure power adapter is removed.
Remove the bottom cover of the MacBook Pro (take note where the three long screws go).
Locate the power connector cable for the 'non-removable' battery (next to the memory modules).
Preferably using a small flat tool such as a small flat screwdriver or such, carefully pry the connector upwards by its edges until it comes off.
After a brief pause, reconnect the battery connector. This may cause the system to start up and fans etc. to activate.
Check to see if the screen is on and indicating startup and also press battery indicator button on the side to verify that the indicators light up.
* If the system starts up normally, you can shut it down, replace the bottom cover, attach and plug in power adapter, verify the charge indicator lights up and perform the SMC RESET as linked In the above post for models with battery you cannot remove yourself and as I describe below.
* If the screen has not come on during the 'startup activity' then hold down the power button to force shutdown. Replace bottom cover, attach power adapter and verIfy charge IndIcator lIghts up, THEN perform the SMC RESET (Hold down left side SHIFT-CONTROL-OPTION keys whilst simultaneously pressing Power button for a few seconds, then release them together). Then press power button again to start the system and check normal operation. You MAY have to reset date and time.
Hope this helps and saves a trip to the Genius Bar.