is the lock on?
i actually did this once- i was using two cameras and one card switching back and forth- and in the process, turned the lock/hold on. check and see if that is the case.
if not, take a look at the contacts- are they damaged? if they are broken, the card is gone forever anyways- try plugging it into a card reader and see if it works then
hope that helps
Nikon D50...Awesome DSLR
-SLR Equpiment: 18-70mm, 55-200mm, and 14mm prime
Nikon L12- just died, sent in for repair, no idea when it will get back