MichaElk Thanks for the input.
As an update I found a suggestion for getting the Mandrake 10 CD's to install which worked. That was to F1 then "expert ide=nodama". I was then able to upgrade from Mandrake 9.2 to 10.
I was hoping this would fix my problem. It hasn't.
It has however changed the fstab which now reads
" /dev/hdc /mnt/cdrom auto umask=0,user,codepage=580,iocharset=iso8859-15,noauto,ro,exec 0 0 "
After the reboot I had two desktop icons one to CDROM one to SCDO. After another reboot the SCDO icon disappeared.
The CDROM icon is connected to the CD as an eject command opens the tray. However attempting to access a data cd causes a freeze.
There is no cd entry in the mtab but I have not had time yet to follow this up, and have also lost my modem.