either the floppy cable came loose....
or maybe the floppy controller on the board died.
or the floppy could have died
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you can troubleshoot it by checking the connections and maybe swapping out the floppy etc
if the controller is bad you may be able to boot into the bios and turn off the floppy controller so the message goes away...but then of course you wont have a floppy...but you can always get a usb floppy