Clearing the PRAM on a MAC

Clearing PRAM is a way of resetting PRAM (NVRAM on Macs) back to its original factory values. Note that this only works on Intel based Macs. 

To clear the PRAM on your MacBook, follow the instructions below:

1. Shut down the computer.
2. Turn on the computer.
3. Immediately hold down the following keys simultaneously: Command, Option, P, and R.  This must be done before the gray screen appears.
4. Release the keys after the 2^nd chime.