C:\ shows as an unformatted ghost drive

In Win98/SE my system_file drive C: came back mirrored as H: after a blue screen encounter saying system could not find drive C: After rebooting system hung up and displayed the gray/white screen a couple of times. Turned PC off, waited, checked connections, and started up again. System hung up several times but finally came up but had an additional drive present. Adaptec drive preparer keeps detecting H: as an unformatted drive and unusable. Cable problem, HD failure imminent or what? Thanks!