Answer to: Changed batteries and it doesn't power up after that.I found the solution on the apple forum: Take all Batteries Out. Roll up a small piece of Tin Foil about the size of a Pea. Drop the Tin Foil Ball down the Battery Compartment. Put your Batteries Back In. You should have a Working Keyboard. This worked for several people on here including me. I'm still running 2 months later with my rolled up piece of Tin Foil in my Battery Compartment. I know it sounds Crazy. That's what I first thought. Apparently Apple did not make the + Terminal Inside the Keyboard correctly. Try it. What have you got to lose?