Same thing happened to me... But I think I know what caused it and found a solution:
I plugged in a bluetooth headset but accidentally used a charging cable for a Motorola handset (nice move Motorola making that the same ends as a USB cable)... The headset seemed to discharge so I thought I'd fried the MBP but hoped it maybe went into protect mode and would need resetting...
It seems this was the case as opening it up and disconnecting the battery for 5 minutes has restored power.