Question
Why do I receive an error message "Cannot Find CD-ROM"?
Answer
The error "Cannot Find CD-ROM" is most commonly associated with users having multiple CD-ROM/DVD/CD-RW drives.
If you have two (2) drives, please put the second game CD in the other drive. This should solve the problem.
If you don’t have more than one (1) drive, then you most likely have put the game CD into a drive that has no CD-ROM capability. Please make sure the game CD is placed in the same drive letter that you used to install the game.
The only other reasons why this would happen is if you have a defective disc or if you have an illegal copy of the game.
http://westwood.ea.com/
This is from there support and then faq from tiberian sun