Re Panasonic DVD Model DMR-EZ27EB?

I recently purchased new recording discs for the DVD (Sony DVD-R) and when I tried recording with one on the unit a message told me that the disc was not recognised and was probably dirty or of poor quality and try again. I tried another disc and the unit tried to read it and came up again with the message 'NOREAD'. It now comes up with that message with every disc I try, even the commercial pre-recorded discs that it previously played back with no problems.

I have also noticed that when the unit is switched off the display panel does not show the time, nothing is shown in the panel. Also, when I use the function menu it does not list the DVD Management feature for formatting etc.

I would appreciate if you could give me advice if anything could be done to overcome the problem.