The trouble you mentioned about your fathers monitor switch is usually due to a dirty waffer switch. Dust gets in there and mucks up the contacts on the switch, giving strange results from no picture to missing color or loss of sync. The active switch I have does not use a mechanical switch, it uses push buttons to activate the switching IC's to change the source for the monitor. If you run in very high resolution mode, its best to use the active switch.
Be carefull tho, if one computer is set up for lower resolution and one is set for high resolution, and you switch between them, dont be suprised if your monitor decides to go into "HV shutdown" due to the instant change in H and V sync frequencies, which usually ends up in a blown H output transistor and or fried high voltage transformer (flyback). Then you start to see smoke escaping from the monitor!! Set everything up right and you wont have any trouble!
RFB