CDROM Not Recognized

I received a donated computer for our school which the donater said the harddrive had been formatted. (a Dell PowerEdge 2200 computer).

My problem… when I go to re-install the Windows 98 OS it does not read the CD ROM so I cannot install my OS. I had this problem once before and am totally blank on how I fixed it.

Can you please give me step by step instructions on how to get the computer to read the CD ROM so I can install an OS and get make this computer usable?

THANKS!!