When I first set up a virtual machine in Parallels, I had some issues with the Windows XP installation. When I reinstalled, I ended up with two XP operating systems. When I start Parallels, I get a screen that allows me to choose which of the two XP OS's I want to boot, defaulting to the first on the list in 30 seconds if I don't choose. I would like to get rid of the second of these two, which I don't use. How do I do this without disturbing the one I want to keep?