I have seen a problem where clicking on the Object Repository button after switching from dual computer monitors to 1 monitor does not open the OR window because the x,y coordinates of the OR window are now out of the viewing area. Here is a way to fix that.

1. Open QTP
2. Left Click mouse once on the Object repository button on the toolbar (don't click anywhere else)
3. Hold down Alt on the keyboard and hit the space bar
4. type m on keyboard
5. hit 'left-arrow' key on the keyboard
6. move your mouse until the Object Repository Window comes into view
7. Left Click once on the mouse again to let go of the window
8. Close QTP and reopen it to verify the fix.

Have you tried to run a Repair on QTP? This is a feature That was started with QTP 9.5 forward.