Missing A Drive

We have upgraded our NT4 workstations on the network to windows 2000 with Spack2. All PC’s have Floppys installed but since the upgrade to 2000 some PC’s about 4 are having a problem where the A; floppy drive doesnt work.It appears to be missing, like it is not installed. I cant see it in disk administrator but when we first upgraded the floppys did work on these PC’s only in the last couple of days have they dissapeared