Why does my DVD drive spin up every minute or so, spin down, and repeat (new Dell Studio 15 with Windows 7)

Why does my DVD drive spin up every minute or so, spin down, and repeat (new Dell Studio 15 with Windows 7)

We have just got a new Dell Studio 15 laptop running Windows 7 home premium with slot load DVD drive. If there is a DVD drive in the drive, every minute or so, the drive will spin up, make a couple of noises like it is reading something and then spin down.