Computer floppy disks have built-in write-protect features that prevent the data on a disk from being removed or overwritten accidentally. If you receive an error message when attempting to save data on a floppy disk in Windows or DOS, the disk's write-protect feature is most likely enabled. After you have confirmed that the data on the disk is safe to overwrite, remove write protection to save data on the disk.
Wait for the access light on the front of your computer's floppy disk drive to turn off. Push the button or flip the lever on the drive's front panel, and slide the floppy disk out of the drive.
Turn the disk so the back faces you if you are using a 3.5-inch floppy disk. Push the plastic tab in the corner of the disk down, toward the bottom of the disk. The tab should now cover the small square hole on the corner of the disk.
Remove the tape from the corner of the disk if you are using a 5.25-inch floppy disk. You should now see a rectangular cutout in the corner of the disk.
Return the disk to the floppy drive and save the desired data to the disk.
If you have a 3.5-inch floppy disk with no plastic tab on the back, cover the hole in the corner of the disk with a piece of tape to enable writing on the disk. If you have a 5.25-inch floppy disk with no notch in the corner, cut a rectangular hole in the top-right corner of the disk -- with the label side facing you -- to enable writing on the disk. Do not do this with a disk that has data you cannot lose, as an incorrect cut could destroy the disk.