I don't think that model has a physical slider for write protection, do you need to try wiping it fully and starting over with a new partition. This will wipe all data off the drive.
Open a command prompt and run the diskpart utility.
In the utility do a "list disk" command, note which drive letter that USB stick has.
Do a "select disk X" command where X is that drive letter.
Do a "clean" command, that will wipe the drive partitions. Make sure you do this on the right drive letter or you can delete data in a second on the wrong drive.
Open Disk Manager and create and format a new partition in that drive.
If this does not work, the drive could be damaged.