Abstract: A casing for electronic equipment, such as personal computers (PC) and/or their peripherals, comprises a base (17) for supporting the mechanical and electronic components and a cover (12) removably fixed to the base in order to enclose the components. The casing comprises a locking mechanism or knob unit (24) which can be selectively actuated in order to lock the cover (12) to the base (17). The knob unit (24) is located in the right-hand side wall (14) of the PC and is associated with a similar unit located in the left-hand side wall, so that the cover (12) can be removed in order to access the internal mechanical and electronic components without the aid of tools. The apposite operation, i.e. fixing the cover (12) to the base (17), is also effected by means of the knob unit (24), again without the aid of tools such as screw drivers or the like.