I installed Kubuntu 15.04 in virtual box on a Windows 7 Pro 64 bit host. It installed fine and so did guest additions. However, when I boot up the machine, I am able to log in, but when trying to launch anything, it doesn't display. It shows up on the task bar at the bottom of the screen, but I can't see it. I have tried clicking on it. It worked until I installed the guest additions and switched virtual box to display two monitors. I have tried switching it back to only one monitor, but the issue persists.