I would first make sure that its not your disk that is fualty. Or make sure that it is formatted. If it isnt make sure your floppy disk drive is okay by checking it using Device Manager. If not it could be a simple problem like your IDE cable has come loose inside the machine, as it once happend to me. This can be resolved by taking the cable out from the back of your floppy drive, make sure that none of the pins are bent on the back of the drive then firmly re-insert the cable. If it isnt that then it would probaly be cheaper to buy a brand new floppy drive as they obly cost around £10.