CD drive fails to show contents -- How to solve it? -- Clarification

[Benjamin Sher]

Dear friends:

I did install my Scientific Linux system from data CD's, using my 
CD/CDWriter drive (hdc). But now it turns out that I cannot transfer any 
of my data files from a data CD to my computer using my CD/CDWriter 
drive. I can only do it using my DVD drive, whose contents show up 
correctly in File Manager.

Thank you.

Benjamin