In general I would usually check nero's website for an updated demo version of nero
http://www.nero.com/us/nero6-ultraedition.php
(this was for a pc that only needed to burn rarely). Generally the demo versions are good for a limited time (up to 1 month, specific date range coded in the demo) before nero has a new version that changes the trial date range. I just checked and it looks like the last demo that they had is already "expired" and that they don't have a new one available yet. this is the explanation as to why your demo was expired before being installed.