There are two Sierra Windows games that can be executed only once without rebooting on at least 3 very different machines of mine. Shivers two and Betrayal in Antrara. There seems to be no processes left running outside of the normal ones that are always running. I don't know if they are attached to some existing process and only allows one incidence of it or what. Neither game's window can be moved -- both are fixed at the center of the screen.

I recently made an interesting discovery. If after I exit one game and start and exit the other, I am able to start the first one again without rebooting. Any thoughts or ideas about what is going on or how to fix this?