Windows 8 is pre-activated for Right to Left Languages. You don't need any activation. Only go through following steps
1. Install Keyboard
Download
KHOWAR KEYBOARD
=> Extract downloaded Khowar Keyboard Zip Folder => Setup => yes => close
2. Install Khowar Font
Download KHOWAR font =>
Extract Downloaded Khowar Font's zip folder => Install
Open any text editing application like MS Word => select Urdu language => select Khowar Keyboard => select Nafeespakistaniwebnaskh font => start writing.