i need help

i have 2 pc,s brought to me. both came from a local collage. both have the same problem. i was asked to remove all collage data & reinstall win. 98. i [cleaned] fdisk, formated. & installed 98.at the last of install, plug & play, ect., it lost the cdrom. i have retried 5 times and still the same results. is there somthing on the motherboard thats causeing this or what? please help me.