Intelligent IT support:
Something was wrong with my touchpad or the mouse. The cursor seemed stuck to one corner of the screen. Tried everything incl. re-installing drivers.
Called support. Guy comes, looks at it for a while. Tries moving the mouse around, tries tweedling the touch-pad. Goes to mouse_settings, increases mouse speed, calls up his sup and tells him "I've done some settings. Let's wait for a while and see". Duh!
Turned out there was a hardware problem with the touch-pad.