Try disabling the Office Startup Assistant (OSA) in msconfig - Startup. This useless piece of MS Office is intended to speed up Office finding and tracking files, but all it really does is to slow down the computer. It could well be repeatedly trying to track non-existant files on the floppy drive.
This nuisance seems to vary in severity but sometimes can be caused and cured by :-
When "Sis" has finished copying to the floppy, ask her to remove the floppy and to open another word document on the PC's HD. Then close that document and Word itself. Hopefully next time the computer is used it will have consigned the floppy access at least one place down in the opening order of things.
So a feeble suggestion now, is to open a Word Doc. from the HDD play with it and save it, and then close all the way down. Cross your fingers and boot again from cold.