Actually, if we're going to get into piddly little bits of legal stuff, you might want to read the liscence you get with your game/proggie. From memory they usually start with something like "<Company Name> Retains posession of this game/piece of software at all times, and all the rights associated therewith".
Turns out (so far as I can see) you never own a piece of software, just the liscence to use it. It just so happens that when you buy the license it comes with something to give you access to the software, but you never actually own it as such.
Anyone able to correct me on this, please do, but I'm pretty sure its right, unfortunately.