Theft protection for electronically-powered articles

A system and method for protecting an electrically-powered article, such as a personal computer, from theft by rendering it effectively useless to anybody but the rightful user/owner. A personal computer includes a real time clock (11) to which electrical power must be applied even when the computer is shut-down (switched off at switch 12). Hitherto an internal battery has been employed. It is proposed that the continuous power is provided by means of a mains-supplied power unit (10). In the event of mains supply discontinuities longer than a predetermined short time period, as would be the case if the equipment is stolen, subsequent start-up of the computer is prevented until a theft protection password is provided by a potential user. A separate power source, such as a capacitor (20), is provided to power the real time clock for shorter time periods, such as when moving the computer within a premises, and thus obviate the need to enter the theft protection password upon such occasions.