Click of death
Slang used to describe when a computer hard drive actuator, arm, or head are malfunctioning and not able to move properly, preventing the hard drive from being able to read or write data. 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 has been 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.