AFAIK, there's no way to unlink a copy of a game using steam's DRM engine from your account, and unless it's a pirate copy, it won't work without steam whatsoever (it will require steam to be running in online mode before even launching the game). As soon as you link it, it's yours and yours only, and there are hardly any exceptions.
There have been some cases of refunds and "product unlinking", but they were very rare cases. Usually, a refund gets applied in the case one product is deemed 100% unplayable on your machine with attached proof of that fact and only if you couldn't know beforehand.
As an example, some games not too long ago were published on the steam store with simple hardware requirements, while they didn't say anything about DirectX requirements. Some people who got the game with a dx9 card managed to get a refund because the game asked at least for dx10, but it wasn't specified anywhere, and thus they literally didn't have any possibility to play.
If the game isn't using steam's DRM engine, however, it depends on the original retailer.