USB Floppy Drives not working, always want me to format disk

My dads business has old machines that only accept data through floppy drives. They recently got a new computer with no floppy controller on its board, so he ask me to come up with a solution. I bought a USB floppy drive and a USB card with an internal port to mount the external drive internally....but I can't get the drive to read a disk reliably.

I have tried two drives now, and have tried them both on an XP and Windows 7 machine. Every disk wants to be formatted, and every format fails. Upon searching I discovered this is a common occurance.

What causes this and how can I fix it? I've tried multiple drives and multiple disks, something fishy is going on. I got the current drive I have to read two disks last night, now this morning it wont read any.

If you have anything to add at all, thank you

Do they work if you connect them to a motherboard USB port instead of the USB card?

Are the floppy disks readable on the old computer? Floppy disks are really unreliable, there are common cases where the read/write heads on a drive get mis-alligned and disks written on it will only be readable by the original drive they were made on.

If it is readable by the original disk drive, you need to make images of the floppy contents, then you can use that image to write on the new drives.

Have you tried using new disk with the drive?

Take out the floppy from the dead system and install it in another computer. And make sure you create images of the disks if you get them to read. If you actually told the system to format the disks when it asked you to you could have wiped the data off them already though.