Here are the answers following :
1) Did you purchase Fences through Steam or Stardock directly?
I believe that I purchased it through stardock website directly
2) Have you successfully activated it in this system or any other system before?
Yes, I did activated Fence 3 in my own laptop.
3) If the Email used to activate it linked to your purchase. ie. If you paid using paypal. The email link to the activation key will be the email that link to the paypal.
I tried with both my product key & e-mail adress(not papal), but it didn't work