I just got my laptop less than a week ago. When I pick it up and carry it around with the screen open, it makes a clicking sound. why?

That's the hard drive heads getting parked/locked back into place to keep damage from happening on it. It's a safety measure, but it's not usually a good idea to be too rough with it while that drive is spinning.

It is the Sudden Motion Sensor in action.

http://support.apple.com/kb/HT1935

Best.

Regardless of what this article says, DO NOT disable the SMS ability. You'll kill your drive over time if you're in the habit of moving your laptop around without spinning that drive down first. Leave it on, it's there to safeguard you like I said in my initial response.

Thanks for the apt reminder.

The article is from Apple and it explains SMS in entirety.

"What if" condition is explicit in itself.

There is no suggestion to disable it.

Best.