In order to fix the issue, connect again the iPod and wait Windows to recognize the device. After that, right-click on the Mass Storage/New Device/iPod icon from System Tray and select the Safely Remove option. Disconnect the device and check the screen. Alternatively, go to Start, click Computer, right-click the iPod drive and select Eject. If it doesn't help, you need to reset the iPod following the instructions provided by Apple.