Aslam o alikom

mara pass 2 memory card hain Micro ka chota wala cards. ak 256 ka ha aur 2nd 2gb ka but dono ko jab card reader ya mobile main dalta hoon to dono work nahi karta. computer main ya error ata ha please insert a disk into drive I . please help me kaya in ka koi hal ha theek karna ka ? thanks