After removing the old battery and installing the new battery I powered up the MBP before screwing the bottom on. I discovered the my keyboard would not function. It took a few hours of investigation and frustration that I discovered the track pad power ribbon had become partially dislodged from the trackpad. I was able to see that this through the little machined slot where the battery sat. I had to remove the trackpad to reinsert the power ribbon back into the connector in the trackpad. after reassembling and reinstalling the battery etc the keyboard worked. Just food for thought if your run into the keyboard issue.