Hi 
As long as you know at least 2 things about your purchase everything is fine.
Just email sales@stardock.com and provide some information.
The sales team requires at least two of the following: your full name, address at the time of your last purchase with Stardock, order number, serial number, or Stardock.net password.
So, your copy of Demigod isn´t lost 
Greetings,
Nokthra