it works good on one of your PC, but there's this bug on the other one ?
This is probably coming from TE2006 thinking one of this happens :
- right mouse button is always pressed => try to press & release it one time to see if it fixes the trouble
- left ALT key is always pressed => same, try to press & release it one time
- button 2 of your gamepad/joystick is always pressed => again, try to press & release it, and if it changes nothing, try to unplug it to see if it's getting better or not
What is your keyboard ?
If none of this helps you, send me your "System.log" file from your TE2006 directory (usually, under "C:\Program Files\Tennis Elbow 2006\").
Copy/paste it here, or in the mail form here :