Overview
For whatever reason you “don’t have” CD Key after purchasing the game.If you check your library you dont have access to one when clicking the game and looking at the right side.So if you wanted to get the game on GoG for free you’d be out of luck. No more though.*Some people have reported this not working. Well i only purchased the game recently and it did. Try it out.
Path to the key in the registry
Just press start(windows key)+R and type in “regedit” and then press enter.
Navigate to HKEY_LOCAL_MACHINESOFTWAREWow6432NodeGSC Game WorldSTALKER-SHOC
And there you go.
Now you can grab your key and go over to GoG[www.gog.com] paste it and get your DRM free copy which by the way is the worldwide version if i am not mistaken while Steam uses the US version.