How do you reset PRAM

resetting NVRAM/PRAM http://support.apple.com/kb/ht1379

1. Shut down the computer.

2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.

3. Press and hold the Command-Option-P-R keys.

4. Turn on the computer.

5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.

6. Release the keys.