The File Replication Service (FRS) on a Windows 2000 domain controller, or a Windows 2000+ server with DFS replicas, causes your floppy drive to activate?
If you inspect the FRS debug logs, you will see entries similar to:
<FrsBuildVolSerialNumberToDriveTable:1368: 1296: S1: 11:34:57> WARN - GetvolumeInformation for A:\; WStatus: ERROR_NOT_READY.
FRS should be bypassing removable media drives when it builds the drive table, but it doesn't.
Microsoft is aware of the problem, but does NOT yet have a solution.