Your Memory Card got
corrupted, and you can't format it using your phone's Built-in Formatter. Stop here and see
if we can repair it.
All the memory card are based
on the FAT file system and
not the FAT32
or NTFS file system. We will need a memory card reader, and a PC, obviously.
1) Insert your memory card in
the mmc reader.
2) Find the drive in 'My Computer'
3) Right click the selected
drive and select Format NOT the quick format.
4) Now, in the file system selection part, select FAT and
not
FAT 32 or NTFS file
system.
5) Start formatting.
-If your memory card still won't work, buy a new one.