Opus displays a drive that doesn't (correction: does) exist

Hi,
Opus suddenly displays a drive that doesn't exist in the tool bar (drive A:). How can I get rid of it ?
Thanks.

What is the command behind the button which is showing that drive?

Are you sure the drive doesn't exist and isn't just hidden in most other places (e.g. due to being empty)?

"Go DRIVEBUTTONS=cdrom,network,removable"

The drive definitely doesn't exist : there has never been a floppy disk drive on this computer (I've had it for four years).

For what it may be worth, I had a major update of Avira antivirus (free version) and had to remove Malwarebytes as there was a conflict between them.

Edit (I couldn't find an "edit" button) :

I solved the problem : when I had this conflict between Avira and Malwarebytes, I had to open the BIOS and use the rescue CD to boot. This must have enabled the non-existent floopy disk. I disabled it and things are back to normal.

Thanks for your quick support all the same.