How can I fix an unstable cursor?

[Cursor Manic]

When typing, cursor jumps back or above unpredictably.

 

[Peter T. Daniels]

Stay away from your touchpad, or turn it off, or turn down its
sensitivity.

 

[Peter Thompson]

Unstable cursor in Word (Home and Student 2007) with Windows

 

[Peter T. Daniels]

My laptop has a button to turn off the touchpad.

Unstable cursor in Word (Home and Student 2007) with Windows