|It could also be a light issue.|
What type of mouse is your wife using?
If it is an Optical mouse (red light at bottom), then check to see if there is a table lamp near the mouse.
Sometimes the light fall on the mouse in just a certain angle, and it triggers the mouse tracking. Then you get the cursor jumping around effect.
If you do not use a mouse with the laptop, then some of your keys might get stuck.
(Probably Tab and/or Shift.)
Press those keys a couple of times (separately and simultaneously) and see if the jumping stops.
If this doesn't help, it may very well be a software issue.
In that case, I suggest that a computer technician take a look.