1) connect the card reader into the PC
2) Insert the CF card into your the card reader.
3) Right-click the card reader driver. Click "Format."
if you can format, choose the "FAT32" file system from the drop down menu and click "Start" to reformat the corrupt card.
if there is other window show up say " There is no disk in the driver, Insert a disk, and then try again." Then you need to please contact SanDisk Technical Support.