It's me and my floppy woes again...

I'm working on a paper for university (due tomorrow). I saved it on floppy at home and did some extra work on it at university today. I opened and saved it normally --I changed the title of the paper but not of the file. Now when I try to open it at home Word tells me that the path name is not valid and that the file may be password-protected or have a / or a \ in the file name. Could the computer at school have saved it with a password or a different file name, and how can I find out? The "properties" option in the dropdown box tells me nothing. Is there any way of getting rid of the password and accessing my file in time to hand the paper in tomorrow? It also makes a hell of a racket trying to open the file. I've searched microsoft for advice and I can't find any.

Thanks,

Isabel