Why isn't my keyboard working properly?
Some of the buttons on my keyboard have stopped working. What can I do to fix this?
If only a few of the key's are not working something may have been spilt on them and caused them to stick and not function correctly. I would suggest cleaning those keys and if you don't know how to follow the instructions here Sony Ericsson Xperia Pro MK16A Troubleshooting under the Buttons are sticky title.