Usually when windows rejects a disc, it's bad. Floppys have a shelf life and sometimes they just die. It also depends on how many times it was formatted previously, you can only write/erase to them so many times before they just up and quit.

There are disc utilites out there for windows that will force format them but Ive noticed that discs that tend to reject formatting will have write problems later. No use risking data on an old disc I say.

Check out
http://labnol.blogspot.com/2006/09/c...isks-dont.html

For an idea of how to be "constructive" with those old discs!