Hi there,

I don't really think this has much to do with the operating system you're using now. This might be related to the graphics/hardware drivers you're using now or some program settings. What kind of graphics hardware do you have in your new system? A dedicated graphics card or some on-board solution?

Make sure your graphics and mainboard chipset drivers are up-to-date. If it still won't work, try this: Go into the program settings ("P" key) and switch to the "Options" tab. Disable the checkbox "Hardware acceleration for 3D effects", confirm the dialog by pressing "OK" and restart the program for the change to take effect. Now, try whether you can get the 3D transitions to display correctly. Maybe the preview performance won't be very good when disabling the hardware acceleration, but if your graphics driver was the weak link, you should hopefully get at least some preview of the transition now. In addition you should also try this: After you have set a 3D transition at a specific location, click on the [A|B] transition icon again and pick the "Settings..." option in the transition pop-up menu. Here you can customize a few technical aspects of the transitions preview. Try a different software interface for the rendering of the transition and see which one performs best. By default, it should be on OpenGL. Try switching to Direct3D and preview again.

I hope this helps!