It's possible that it has just started off screen.

Once it has opened and you see the icon on the Task bar, immediately hit Alt-Space Bar.  A menu should show up.  If so, hit M for Move.

If the menu shows up at the top right of the screen, use the left and down arrow keys to bring the window back on screen.  If it is at the bottom left, then use the up and right arrow keys.

Thank you. 

We have SAGE 50 Pro Accounting.  I see there is a SAGE 50 Premium Accounting.  How much more is it per year and why should I bother upgrading to Premium?

I found my own answer.  I searched the knowledge and I found a summary of the differences.