Lets see if a Hard Reset solves this for you.
Unplug the power cord and shut the unit off and Press and Hold the power button and the Down volume button together for 6-10 seconds and let them both go. You should see a little shape in the middle of the screen so just press and release the Down volume button again and let it reboot. If you own the dock be sure and do this with the dock connected.
Let me know if this works.