Abstract: A computer (10, 11, 12) is provided with a physically-removable resource in the form of a smartcard (20) including user logon information (for local and/or remote resources). Upon at least the removal of the smartcard (20), different behaviours are produced depending on whether a predetermined keyboard key, such as the ALT key, is depressed. Thus, assuming that the smartcard (20) has been used for logging on, then upon removal of the smartcard if the ALT key is not depressed, a logoff procedure is effected whereas if the ALT key is depressed at the time the smartcard (20) is removed, an alternative behavior is effected such as the display of a user option menu. This approach of causing the behavior of the computer to vary upon resource removal in dependence on whether there is a current sustained operation of an input device, can also be applied to other types of removable resources and input devices.