I believe the tooltypes override the DOSDrivers entry (mountlist). In any case, it can't hurt to change the entry itself. You should turn the CD-ROM file system in the CSPPC boot menu off if you use the DOSDriver entry. CD0 must be in your Devs:DOSDrivers drawer for it to start at bootup. You can start it anytime, anywhere by double clicking CD0. The SCSI address has to be correct. If there is still a problem with no error messages then your CD-ROM drive probably doesn't like the 3.9 CD.