Parallels 10 problem with key

[MatteoR1]

Hi
I've bought Parallels 6 some year ago, and last year I've bought the update to version 10. Now, I've re-installed parallels on my mac.
Now, when I try to activate Parallels, filling key update field and previous key field, It doesn't allow me to activate.
It doesn't give me an error, just doesn't allow me to push on activate button.
Can anyone help me?
Thanks

 

[PaulChristopher@Parallels]

Hi, Customers who are using Parallels Desktop 7 or the earlier versions are not eligible for upgrade pricing for Parallels Desktop 10 for Mac. If you have Parallels Desktop 8 or 9 you can upgrade to Parallels Desktop 10 for Mac. You may also find the license key using this article