There are a few ways to tackle this. It looks like MC is using an incorrect setting from the Mac in Windows, instead of re-detecting the optical drives in the Windows PC, as it should.
First, can you confirm that you have two optical drives in the Windows PC, designated as D: and E: in Windows Explorer? This is important.
Next, go to "Options > File Location" and just check that there aren't any unusual settings in there for any of the defined paths. I would be looking for a setting just pointing to "/" or "/:" for example. Fix any incorrect settings. If there were any to fix, restart MC, and check the "Options > CD, DVD & BD > General > CD Ripping" section again and see if the incorrect setting is still there.
The next easiest thing to try is as follows:
1. Make a Library Backup of the MC27 Library that you have. Make sure you know which backup this is, and keep it safe. Using this Library for the fix will save any changes you have made in it, but you are going to lose your settings in this installation.
2. Uninstall MC, including the Library and all settings. Reboot the PC.
3. Reinstall MC27, stop the automatic import process in the Action Window (bottom left, message and countdown) so nothing is imported, and then check the "Options > CD, DVD & BD > General > CD Ripping" section again and see if the incorrect setting is still there. It shouldn't be there. If you do have two optical drives, D: and E:, then those should be shown. If the "Drive /:" still exists stop here and report back.
4. Restore the Library from the backup you made above, but do not Restore settings.
5. Check the "Options > CD, DVD & BD > General > CD Ripping" section again and see if it points to the valid optical drive(s).
Then you will need to go through all the MC Settings again and put them back the way you want, as they will be defaults after the Restore.
Try inserting a disc into one of the drives again. Does it work now?
If that doesn't fix the issue, come back and ask for more help. This could also be fixed using the "User Settings.ini" file from a backup, or by editing the Windows Registry. The latter would save any settings you have changed in the Windows installation of MC, but has some risk involved.