CD/DVD Rom on Presario 7478

The CD/DVD-Rom on has started to not read read any discs inserted in
it. The drive shows up as OK in the Device Manager and is "pulsed"
during system startup. However, when I place a CD in the drive, the CD
will not autostart and when I click on the drive from explorerI get a
message "F:\ Is not accessible. The drive is not ready." The G: drive
(CD-RW) drive does the same thing. Since the hard drive is working ok
it see that I must have either a bad connection or a bad IDE ribbon
(break in some but not all conductors?). I checked the conections and
they all seem clean and firmly inserted.

I suspect that somehow I damaged the IDE ribbon when I earlier
installed a new hard drive.

Does my guess as to the cause make sense? Is there something else I
should check?

Oh, is there a specific IDE ribbon that I would need to replace the one
that came with the machine? Hmmm as I write those words, it hit me that
maybe the ribbon that is in there now came with the Zip100ATAPI drive.
I removed that drive when I worked on the hard drive, to make room for
the old drive to copy data off. But since the CD drives worked after
that, seems like it must have failed later - IF that is what is wrong.

All help appreciated!

Steve