I had Sonar X3 installed in my old computer, and Melodyne worked perfectly.   I recently bought a new computer and re-installed Sonar X3.   Everything installed without a hitch.   But when I opened Melodyne, a box came up that says I need to license it.  When I typed in the serial number from my Cakewalk account, it says it's incorrect  (and yet in my Melodyne account, that's the serial number I used with my old computer).
 
I read in the box that I was to go to "Help" in the Melodyne window and click on "License."   Nothing happened.  I emalied Melodyne, but their suggestion to open Melodyne in stand alone and run as administrator didn't help either.   
 
Any suggestions?
 
Thanks!
Greg

Try it after each step...
 
Try temporarily disabling your firewall...
Run windows update everywhere.
Uninstall/reinstall Melodyne.
 
Probably best to check this thread first though:
http://forum.cakewalk.com/Melodyne-Registration-Nightmare-m3164464.aspx
 

I finally got it working - although I'm not quite sure how I did it.  
Thanks for your help!
Greg