Go into the menu settings on the camera and there should be an option to format the card. Be sure to take anything off of it you want as it will delete everything
I couldnt find anything in the settings.
1.resolution
2. Spot meter
3. Upside down
4.quick capture
5. NTSC/pal (wtf does this mean)
6. Led
7. Beep
8. Date and time
9. Delete
10. Exit.
Edit: in the delete menu there is a format.