The Microsoft Scripting Runtime Library offers a FileSystemObject and a Drive object that allow you to check if a Floppy drive is ready. Before writing the code you have to add this library to your project using the References dialog window. If the library isn't contained in the list, you can download it from Microsoft web site at www.microsoft.com/scripting.
With the FileSystemObject's GetDrive method you get a reference to a Drive object that points to the drive you've specified. Test the drive state through IsReady property. Here's a very compact function that contains all the code you need:
' Test whether a drive is ready
Function IsDriveReady(sDrive As String) As Boolean
Dim fso As New FileSystemObject
IsFloppyDriveReady = fso.GetDrive(sDrive).IsReady