Can't read A drive

I just installed Windows xp sp3 on an older Compaq workstation. When I try
to read a file on the A drive I can get the list of files on the floppy but
I cant read any of the files even .txt files. I get messages like "cannot
read theA:readme.txt file or in another case "the folder is invalid or
corrupted" I can use notepad to write a file and then write it to the
floppy and I can read the file back My objective in all this is to load
windows 3.1 into the virtual machine Sun virtual Box. When I try to load
the boot disk using virtual box I have the same problem.