I have a Teac USB portable diskette drive, N533. Until recently, it has worked okay. However, it has started not opening any diskette I put in and instead a message appears that the disk needs to be formatted. Even when I try to format it, the message will then be that Windows cannot format this disk. I have tried various disks and all with the same problem. Disks will not open and even show me the files which I know are on there. The device worked until yesterday. I have tried switching USB ports, restarting computer, etc., but nothing seems to work.

Click start control panel administrive tools computer management device manager scroll down universal serial bus controllers you should see a yellow question mark?
right click to reinstall drivers
if you can see your usb drive but its not working
ports(com&lpt)right click update driver if this fails to fix the problem
check the USB leads that attach to the motherboard usually red white green black make sure they are securely seated and have no dust build up on them dust will cause static and a lot of unforeseen problems for a computer and its parts also
scroll to disk drives if you can see your drive + to expand right click you should see options update driver disable uninstall scan for hardware changes
select properties you should see options in the general tab to troubleshoot policies volumes driver and details under the driver tab you will have the options to check the driver details update driver rollback driver or uninstall
hope this helps