Splatsch: Of course, don't worry for that ;)
Dartpaw86: :)
Yeah, despite some peoples' negative opinions about GOG, they're not monsters. I mean if this happened on Origin, even EA would have to refund.
I think too (even if I never used Origin) if a game is broken, there is no reason you can't be refunded.
In top of that, always remember on GOG that if a product should work on your computer and don't, you can ask for a refund during 30 days after the purchase (that's the "MONEY BACK GUARANTEE. 30 days coverage after purchase.").
And if you bought a game and didn't downloaded anything of it, you can ask for a refund (you "cancel" your buy). I don't know if it's for 30 days too, but I know you can cancel a purchase (of course if you don't abuse of it, and haven't downloaded the game and/or bonuses ;)).
GOG aren't perfect, but for me, they're good :)