Power Button doesn't work.

The power button is part of the keyboard so you must replace the whole keyboard. A replacement keyboard for your MacBook Pro is easy to find on many places on the web just search for "A1278 US 2010 replacement keyboard", you should pay $30 for a new one. To replace the keyboard you must remove the logic board, the DVD drive , the backlight layer and + - 80 small philips screws. You should order the keyboard and the backlight layer cause the keyboard backlight is often damaged during removal. Check on youtube for a keyboard replacement tutorial.