2 of the thing happen to your either the mobile or the phone1. if your phone is reading other memory cards and working fine(not slow, few functions not working) then your memory card either being corrupted or have virus. Attach your memory card to computer to scan it and if does not open in computer or it is not read by computer then your card is corrupted and if it has virus found after you can you must try to format your memory card through the computer after taking up a back up.2. if your mobile is not working fine or your memory card is working fine in other mobile that mean your mobile has a virus and you need to format your mobile.check these thing and if your problem solves give stars to me or if any of condition is there and you not find what to do you can contect me on TRICKER