Ok, I've never used Steam, and I've heard some pretty bad things about it as well as some good. When I order my new PC parts I'll have 2 vouchers for games from Steam, however my frankley pathetic download limit won't allow me to get the games 
However, fear not because I have friends, and I'm sure I'll find one willing to get both of the games for me, burn to disc and if needs be, send them to me in the post, I'm just kinda worried about if that will work or not? Is there some lame software that means only the downloading PC can play the game or download in the future? Actually, can I re-download the game if my PC crashes and burns, or is it a download once kind of thing?

However, fear not because I have friends, and I'm sure I'll find one willing to get both of the games for me, burn to disc and if needs be, send them to me in the post, I'm just kinda worried about if that will work or not? Is there some lame software that means only the downloading PC can play the game or download in the future? Actually, can I re-download the game if my PC crashes and burns, or is it a download once kind of thing?