Dedi,
driver programming (as driver modification in fact is) is not the easiest step to begin with. But anyhow, most of your Qs are simple if one knows how to:
* Check if you can open the driver by doubleclicking its icon. If not you have no chance. Else...
* Check how the information for display A & B is gathered and if the infor for C is also there. If required add code to gather this info (this is the hard part!).
* Add a display on the front panel (FP) of the modified driver and modify it to display all required info for C.
* On the block diagram (BD) connect the output of the gathered infos for C with the terminal of the new display.
* On the FP right-click onto the VIs icon, choose 'show connectors'. Choose the wiring tool, click on any free connector pad
(right-click 'add connection' if necessary) and than on the new display.
* Again right-click on the icon, choose 'show Icon'. Double-click on it and the icon-editor opens.
FINALLY DON'T FORGET TO SAVE AS A NEW VI, as this preserves the primary vi as well as your modification (in case you update or repair the primary driver).
You may have a look at www.searchview.net for a quite good LabVIEW-FAQ and and the discussion list Info-LabVIEW.
HTH!
--
Uwe