Uninstall and reinstall Nero. If that still fails, it is most likely the drive that has failed...
www.nero,com
download the replacement there...
Darn comma instead of a period...
What version do you have installed?
Prior versions:
http://www.nero.com/enu/downloads-previousproducts.html
Free version:
http://www.nero.com/eng/downloads-nero9-free.php
If you want 6.3.1.7 let me know. It's too big to e-mail, but I can upload it somewhere for you...
Feature BLOAT for starters...
I will email you something...