A method for providing a user interface for a computer having a processor, a display and a physical keyboard comprising a plurality of keys, the method comprising: presenting on the display, a plurality of graphical keys that correspond to the plurality of keys of the physical keyboard; defining a plurality of symbols (550, 555, 560, 565, 570, 575) for a plurality of output actions that are invocable by pressing one or more of the plurality of keys of the physical keyboard; and presenting a set of the plurality of symbols over a set of the plurality of graphical keys based on an active operational mode of a plurality of operational modes of the user interface, wherein the set of graphical keys over which the set of symbols are presented identify a set of keys of the physical keyboard that correspond to the set of graphical keys and that are usable to directly invoke a set of output actions identified by the set of symbols while said operational mode remains active, wherein the set of output actions identified by the set of symbols are different than default output actions indicated by the set of keys of the physical keyboard, characterised in that the plurality of operational modes comprise an operational mode that becomes active when focus of a frontmost application is on a text field and no characters are selected within said text field, and wherein the set of symbols identifies characters for insertion into said text field using the keys of the physical keyboard, wherein the plurality of operational modes comprise an operational mode that becomes active by a press and hold of an alpha-numeric key of the physical keyboard beyond a certain time threshold, and wherein the set of symbols identifies a set of output actions that becomes accessible using a set of keys of the physical keyboard while the alpha-numeric key is held down. presenting on the display, a plurality of graphical keys that correspond to the plurality of keys of the physical keyboard; defining a plurality of symbols (550, 555, 560, 565, 570, 575) for a plurality of output actions that are invocable by pressing one or more of the plurality of keys of the physical keyboard; and presenting a set of the plurality of symbols over a set of the plurality of graphical keys based on an active operational mode of a plurality of operational modes of the user interface, wherein the set of graphical keys over which the set of symbols are presented identify a set of keys of the physical keyboard that correspond to the set of graphical keys and that are usable to directly invoke a set of output actions identified by the set of symbols while said operational mode remains active, wherein the set of output actions identified by the set of symbols are different than default output actions indicated by the set of keys of the physical keyboard, characterised in that the plurality of operational modes comprise an operational mode that becomes active when focus of a frontmost application is on a text field and no characters are selected within said text field, and wherein the set of symbols identifies characters for insertion into said text field using the keys of the physical keyboard, wherein the plurality of operational modes comprise an operational mode that becomes active by a press and hold of an alpha-numeric key of the physical keyboard beyond a certain time threshold, and wherein the set of symbols identifies a set of output actions that becomes accessible using a set of keys of the physical keyboard while the alpha-numeric key is held down.