I plugged in my Garmin Nuvi 40LM to the computer and got the updates. But my keyboard is still not responding correctly. I push 5 and get a 6 or push T and get a Y. Any ideas?

Try recalibrating the display. Turn off the Nuvi. Place your finger on the upper left-hand corner of the screen and hold it there while pushing down on the power button to turn the unit on. Release the power button when the Garmin logo appears. Continue to press on the upper left-hand corner of the screen until you see the calibration screen.

Press all of the dots as they are presented. Once completed the Nuvi will display Calibration Complete

This will recalibrate your touchscreen to the LCD display. If this doesn't resolves your problem. then your touchscreen may be defective.