Bob they may have sold her the wrong cable. Does she have 1 rca plug (yellow for video) on the other end, 3 rca(composite video), or S-video?
Is there a mixer involved or straight from computer to TV?
Another stray thought.... is the 2nd monitor active (right click on it and see whether it lists activate as an option)?
Is she turning the TV on (and the mixer if connected through) before starting the computer?
It is awfully hard sometimes to troubleshoot via long distance.
