CD-ROM and DOS 6.22

I am trying to repair an old 486 for a not for profit. After reformatting the hard drive and loading DOS 6.22 and the DOS drivers for the NEC Multispin 8V CD-Rom, I cannot get the drive to read. I can change to a D: drive prompt but get a CDR101: Not ready reading drive D error message when I try to make it read. I’ve checked BIOS and can’t even find cd-rom listed in the D drive after user type. They claim that the drive was working fine when they were running Windows 95 before the hard drive crashed. Am I missing some critical files or something? Is the cd-rom cooked?