Mac laptop The computer is frozen. I Zapped the pram but it did not fix the problem. What else can be done?

Resetting Parameter RAM (PRAM)

PRAM stores certain system and device settings in a location that Mac OS X can access quickly. Exactly which settings are stored in the computer's PRAM varies depending on the type of computer as well as the types of devices and drives connected. To reset PRAM:

1. If computer is on, turn it off by choosing Shut Down from Apple menu.

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. Note: If keyboard does not have an Option key, use Alt key instead.

3. Press power button.

4. Immediately press and hold Command-Option-P-R keys.
Important: You must press this key combination before the gray screen appears.

5.Hold down keys until computer restarts, and you hear startup chime a second time.

6.Release keys.