If you are getting "Invalid CD Key," here are the most likely culprits:
: Available at K4G.COM for $4.16 $15.53 . If you are getting "Invalid CD Key," here
Occasionally, budget re-releases place the sticker on the exterior back of the box. 2. Digital Stores (Steam, GOG, etc.) If you are getting "Invalid CD Key," here
: The expansion doubles the strategic possibilities by introducing new doctrines like Royal Canadian Artillery for the British and Scorched Earth Tactics for the Germans. Technical Tips: Keys & Activation Company of Heroes: Opposing Fronts Review - GameSpot 26 Sept 2007 — If you are getting "Invalid CD Key," here
In the context of the classic real-time strategy game Company of Heroes: Opposing Fronts