While running Scandisk a message appears telling me Scandisk has restarted 10 times because a program is writing to the C drive at the same time. But as far as I am aware no other programs are running. If I choose to continue without receiving this message it eventually completes Scandisk. But when I try to defrag the drive in question a message appears telling me it cannot continue because of an error on the drive, and to run Scandisk! Any suggestions would be gratefully apreciated.