Cursor skips -can.t select text

One of the lectora developers I'm supporting has a rather odd problem. She's running Lectora 2007, as soon as she opens up a title and tries to work in it, the cursor begins behaving erratically, progressing in short jumps across the screen. If she clicks on a text box and tries to select text by clicking and dragging, it basicaly highlights each letter, with some lag, while the cursor is passing over the text, but never highlights the whole line.This only happens in lectora, and does not happen in any other programs on her machine. I have had her close lectora, restart and create a new title. The cursor behaves the same in the new title. (One page and a text box) Her current computer is running Vista, but I had her install on an older laptop running XP and the same thing happens. Any clues, anyone seen anything like this? Her copy is VERY unstable and crashes frequently. I have a very frustrated user here and am looking for suggestions/solutions.Thanks,David Davis