Click of death
Click of death is a slang term used to describe the noise made by a computer when the hard drive actuator, arm, or head are malfunctioning. If the computer can still boot, backup all essential information on the computer before the hard drive totally fails. If the computer cannot boot, all information on the hard drive is considered lost and the drive should be replaced.
The click of death is also a term used to describe the clicking noise heard in other removable disk drives such as the Iomega Zip drive and Jaz drive.