AFAIK, Poser doesn't install drivers and stuff, and so shouldn't be affected by an OS install. You may need to check shortcuts, and the settings used to run Poser when you click on a Poser file, just to be sure that the Poser executable is running in the Poser folder. But one possible gotcha: I use XP, and the video drivers supplied through Microsoft have lousy OpenGL support. In my experience, it's far better to use a graphics driver supplied by the chipset manufacturer. What you describe certainly makes me suspect that area of your system. The mouse pointer in particular.