I installed Bioshock (boxed DVD) but only played for a few minutes, on an older iMac. I intend to play it on my next MacBook Air instead (even the current Air benchmarks pretty well with Bioshock, better than my iMac). Since I don’t intend to get a DVD drive with my Air, that means I’ll be re-buying the game as a Mac App Store download. The disc I bought is useless to me. (Unofficial workarounds may exist, but I don’t want to bother.) Can I sell my boxed Bioshock? Is there an install limit on Mac? How many? Any way to "de-authorize" and get one back? It seems there was a limit on PC and then it was raised or removed; but I don’t recall any such patch for Mac. And I don’t know what electronic registration goes on when you install the DVD version. Is it now tied to my name, and useless to anyone who buys it from me used? What’s the deal? I don’t want to sell a used game without being able to honestly state its limitations! Thanks in advance.