OK - got it sorted
Here's the answer:
Open a terminal then type the following:
Dialog pops up.
Click "Add" and a new dialog pops up
In the "Name" box, type something like nVidia Startup
Then in the Command box type:
(The last character is a lower-case "L")
And finally in the comment box type something like "Overscan Compensation"
Click "Add" and you're done. Log out, log back in and it works like a dream.
Piece of cake (or as they say in la belle France, "Un morceau de gateau!")
That's all, folks.