It has been at least 12 hours since C++PHREAK has had music. This could get ugly.
As I understand it, the CDROM worked fine until a new network card was installed. After installation, the CDROM will not play an audio CD, and you cannot mount a data CD.
You checked that the CDROM cable was still securely connected at both ends. It must have power for the tray to work. If the audio cable were loose or something (you may not have one), it would still not affect your ability to mount a data CD.
Does the newly installed network card function correctly?
You might look in /proc/interrupts and make sure that there is no conflict there.
If the problem is already fixed, what did you find?