I want to add some important files to the recovery media I received with my laptop, but it is write protected and I can't remove it.
Bear in mind that you do this ONLY to use the drive for something else - removing the write protection destroys all data on the drive. You CANNOT remove the write protection and maintain the integrity of the data on the drive.
Further, given that 16G flash drives cost as little as $5-10 these days, you're better off leaving the recovery drive as is and buying a new drive for use as a storage device (or make your own image backup using True Image, Reflect, etc.).
If you still want to destroy the data on the drive to allow writing,