Pl. Answer soon.

Sometimes you can't. If its write protected because of a defect in the drive. Which I have seen happens more than a few times over the years.

Assuming drive that don't have a switch on it which is fairly rare.

You could try this,

Remove Write Protection from Pen Drive | Tech Salsa (http://techsalsa.com/solution-to-remove-write-protection-from-usb-pen-drive/)