disappearing CD-Rom drive

In the non-profit organisation for which I voluntarily work we prepare donated portable PC to be distributed to handicapped persons. We use Ghost to reinstall the needed programs and OS on those portables. On some of them, though the Ghost restore works OK (which means the CD-Rom works), after rebooting to Win 98 the CD-Rom disappears and is not accessible !!! Reinstalling Win 98 cures the problem !!! but we loose a great part of Ghosting. Any suggestions are welcome.
Thanks