[Mobhack]

Shrapnel has a thing caled IIRC "safebox" or somesuch. I think it lets you redownload if you have kept your purchase data/reciept.

If buying the game again that safebox (if I got the name right!) thing looks like a valuble "insurance policy" for any future computer meltdown etc - just remember to back up the details on an external drive of some sort if you do so!