What kind of card you have? I've 3, two bricked (A 2nd gen Supercard DSTwo, and a brand new Acekard 2i.) and one that, somehow, still works. (A 1st gen/initial release Supercard DSTwo, cracked case and a missing C17 circuit.)
Bricked the DSTwo when updating the firmware (Updated completed sucuessfully, shut it down like instructions said, turn on insta-brick), and my Acekard 2i bricked itself when it tried running Black 2. (Happened to a number of other people too. Real mad, since Black 2 was the first game I tried playing on it.)
3 DSi's too. One destroyed DSi (Dropped it, SD reader broke. Dropped it again a year later, refuses to read anything now. Would open it to repair, except I damaged the screws when I tried opening it to fix/replace the SD reader), a DSi (3 months old, got it after I broke the other one. Also, have a protective case for it) and a DSi XL (half month old, won it in a contest. Haven't picked up a protective case for it, yet, though.)