Disc Is Not Writable Insert A Writable Disc

I have DVD-RAM drive in my hp laptop and i used to write DVD-R disc usually.
In the recent time i get an message when insert a dvd-r disc. The error message is

The disc is not writable

Please insert a writable disc

Disc required for compliation : DVD R/RW, DVD R DL, DVD-RAM

Disc type in the recorder VD-R

But i used the same disc before and it was half writtened already.

help me to resolve.
Note: burning software nero 7 essentils(nero smartstart)