I have added a usb disk to my system and now my application id is 0.

It is added as C: since my system drive is on D:.

To clarify:
There has never been a C-drive in the pc so ejukebox has not stored any info there ...
I am running a 30 day trial with 23 days left of the period.
I have decided to register ejukebox however it is kind of difficult with applicationid 0...what to do?
reinstall on top of it does not work...

My copy of eJukebox also resorted to applicationID of 0 when I purchased a new hard disk.

I purchased the new disk, and replicated my old disk onto the new disk. Then I removed the old disk and set the new disk as the primary. That's when eJukebox decided to change the appID to 0.

Audiosoft gave me a reg. code to work with the appID 0; but perhaps they won't want everyone having the same appID?

I think the best way is to downlaad EJ again, install it and than you will have a new number.. with that number you can get a new serial (if already had one)