It all hinges on whether you can access your old PC, your XDA and the email account your registered XDPXv10 with!
Open XDPXv10, press Shift+Ctrl+Alt+1 and record the Serial number (P2-nnnnn-nnnnn-nnnnn-nnnnn-nnnnn-nnnnn).
Magix should accept that as proof of licence ownership.

All you then need is the email you used to register it.

Xara transferred your details to Magix so a record will still exist.

Acorn