Do you have any antivirus software installed? If yes, uncheck your setting to scan floppies on shutdown and see if that works.
For the record, every now and then my SP1 box will just randomly try to access the floppy drive for no apparent reason. When I tried to use an HP all in one (printer/scanner/copier), trying to get it to scan would only make the floppy drive seek... seek... seek... until I would reboot! I got rid of it fast.
Tom