The secure digital card is one of the most ideal methods of transferring data from one device--such as a cell phone--to another, such as your computer. It is the modern equivalent of the floppy disk. Many programs come on SD cards--even some movies. To add data to a card, it must be free of write protection; once your card is unprotected, add or delete data at will.
Grasp the SD card with the gold contact points facing you.
Note the position of the tiny white write-protection tab on the right-hand side. The write protection is turned on if the tab is close to the contact points.
Slide the tab away from the contact points in order to turn off write protection.
Turn off write protection by placing a piece of cellophane tape across the notch if sliding the tab doesn't work. Be very careful to only tape the notch and not the contact points. If the tab is broken or missing, place a piece of cellophane tape across the opening where the tab should be.
Remove all tape to protect your data again.