There really is only one remedy we can suggest on a forum like this and that is to return the unit to factory default. This is covered on page 36 of your user manual.
This is the instruction.
There is a feature in Digital Drive that allows you to restore the factory defaults. On the Main
Screen, simply press the 8, 9, and 0 buttons in sequence. If you are successful, the unit will
flicker the video and then restore the main screen. The system responds with a defaults
restored message, as shown below:
Get you manual out and make sure the unit shows the screen depicted on page 36.
If this does not solve a problem like that there is nothing else we or you can do about it. The unit will need factory service or replacement.