How can i download spore.

I have recently found my old spore case, but without the disk.  The disk was in an old computer that broke, when i got the disk out it was so scratched up it wouldnt run. so i threw it out.  The problem is that I want to play Spore and i have my code but I dont have the disk.  How can i download spore on my computer without having to purchase another disk or the online game. I already bought it and wouldnt like to pay for it again.