Seriously, most cereal (boxes) don't require keys. (stress release attempt over)
-> If you can acquire the register receipt, and maybe photo copy something from the disk, etc., MAYBE SD will help you. I think I remember reading somewhere (long time ago) that SD customer service will help if you have proof of purchase from point of sale.
BTW, its a good habit to copy ALL serial numbers to various places on PC, or even a hard copy. Impulse has a feature that will copy your serial number right to the clipboard, making it error proof in copying the number.... I have a small word pad doc with all my serial numbers stashed away in two locations. Just a suggestion to ead off this kind of hassle in the future. Hope SD cust serv will help.