Crash insurance?

Is there any type of “crash insurance” that I can use in the event that I loose my download for whatever reason?

Like, can I get a serial number that I can keep in my email account, and if I ever need to restore my computer to factory settings, I can just type in that serial number where it says “discount code,” and I get a 100% discount?

you can always back up the installer you download to CD. But if you dont want to do that, and you wipe your hard disk, you can then re-download the game again for free, yes.