I think I may have found the answer:
Cannot access a CD-ROM or removable drive after installing Norton
AntiVirus
Situation:
You installed Norton AntiVirus. When you try to access the floppy disk
drive or another removable drive such as a CD-ROM drive or a Zip drive,
you do not see the contents of the drive. You may also see the error
message "Drive <x:> is not Accessible. Incorrect function." (where <x:>
is your removable drive).
You see the CD-ROM drive, but its contents are not displayed. If you
start the computer with a disc in one of the drives, then you can
access that drive; however, as soon as the disk is removed, the drive
again becomes inaccessible.
Solution:
This can be caused by a timing conflict between one of the features of
Norton AntiVirus and another software program that loads on start up.
To fix the problem, follow these steps to disable the Norton AntiVirus
features, restart the computer, and then re-enable the features.
To disable and re-enable the Norton AntiVirus features
Start Norton AntiVirus.
If Norton AntiVirus is installed as part of Norton SystemWorks, then
start Norton SystemWorks.
Click Options.
If you see another menu, click Norton AntiVirus.
In the left pane, click Auto-Protect.
In the right pane, uncheck both of the following entries:
Enable Auto-Protect (recommended)
Start Auto-Protect when Window starts up (recommended)
In the left pane, click Email.
In the right pane, uncheck Scan incoming email and Scan outgoing email.
Click OK.
Exit Norton AntiVirus.
Restart the computer, and then check the drives that were not
appearing.
If the drive does not appear, then go on to the next section.
If the drive appears correctly, then follow steps 1-7 and recheck each
entry.
Restart the computer.
Update to the latest version of CD-burning software
If you use a program named InCD to burn CDs, some users report that the
problem is fixed by updating or by uninstalling the program. InCD is a
product of Ahead Software, the makers of the Nero suite of CD-authoring
tools. If you use Nero 5.0 or Nero 6.0, the problem may be fixed by
updating the program to the latest version. Updates to InCD and Nero
are available at the following Web site:
http://www.nero.com/en/content/download.html.
To fix the problem if you recently upgraded to Windows XP
If you also see the message "Incorrect function," the problem might be
a result of upgrading your operating system to Windows XP without first
uninstalling programs that are not compatible with Windows XP. For more
information, see Article Number 315350 in the Microsoft Knowledge Base
at: "Incorrect Function" Error Message When You Access the CD-ROM
Drive, DVD-ROM Drive, or CD-RW Drive.