These floppy disks fail, They are old technology that really shouldnt have been relied upon so much is another way of putting it. They are fine when they work and hell when they dont.
I use them, but i also know that the next time i use one it may very well not work. So whatever i have on floppy i keep copies of that on cd's or dvd's.
I have a box of about 30 win98 boot disks. When i get a computer in that i have to repair i whip out my box of win98 floppy boot disks. I usually have to try 3 or 4 different floppys before one will work, and its different ones all the time, depends on the floppy drive!
And thats another explanation. The floppy drives themselves get out of spec, the mechanisms get old and worn and sloppy so that some floppy disks will work and some wont.
The more the floppy disk and the more the floppy disk drive get used the closer they both come to failing you.
Your floppy disk may even work in another floppy drive, by the way. Sometimes you just have to re-boot and the floppy that wouldnt work will work. Other times you are plain out of luck.
Even the drivers for these floppy drives are old and very basic.
However, if you absolutely have to get the info from that floppy and you cant get it anywhere else, there are, i believe, ways to do so. I think, but dont know for sure that some of the hard drive progs that troubleshoot hard drives will work on floppies. But you didnt say if you need the data real bad or not.
Good advice + great people = tek-tips