Hey there, amitpattewar1.
Unfortunately in most cases when this happens it's a way of saying that the flash drive might have failed. However, there as some thing you could try in order to see if any of them can fix it for you. Take a look at the suggestions from this article: http://www.wikihow.com/Disable-Write-Protection.
You could also try the flash drive with a different computer and try reformatting it with its manufacturer's formatting tool.
Hope that helps.