A: Possibly. In 2013–2015, Sega allowed key conversion. Today, that portal is closed. Contact Steam Support with proof of purchase.
The Company of Heroes: Opposing Fronts retail code system is a relic of a bygone era of PC gaming—one where we kept paper manuals in CD cases.
If you are holding onto that old retail code, treat it like gold! Register it on Steam immediately to future-proof your purchase. And if you’ve lost the code, don't stress—a digital copy is just a few dollars away and will save you the headache of trying to get 15-year-old DRM software to run on a modern PC. A: Possibly
Now, get out there and hold the line, Commander
A: No. Some very early European retail versions used a 16-digit code for the internal Relic Downloader. These no longer work. You will need to contact Sega support or buy a new copy. A: No
Company of Heroes: Opposing Fronts is an expansion to a landmark real-time strategy game. When hunting for or using product keys and retail codes for this title, a few practical, legal, and historical points make the topic more interesting than just a string of characters.
A: No. Keygens from 2007 are either malware or generate fake keys that will never work with Steam or official servers. You will waste hours and infect your PC. Company of Heroes: Opposing Fronts is an expansion
A: You bought a used copy (e.g., from eBay) or a key from a grey market reseller. Only buy from authorized stores.
Back in 2007, DRM (Digital Rights Management) was harsh. Opposing Fronts used a system where the product key was required during installation. Furthermore, to play online via the now-defunct THQ Online service or GameSpy, you had to create an account and permanently attach that product key to your login. If you lost the key, you lost the ability to reinstall or play multiplayer.