Desktop computer windows 10.9 upgraded from 8.1 2 months ago.) Main screen would come up showing my icons on sign in. I woulld click on the blue window bottom left and my apps would come up. Now nothing happens. However if i right click on it I get a black box with lots of choices. eg search file explorer, shut down, control panel etc. I did not change anything to my knowledge. What has happened? This happens on both my sign in and my wife's too. I can still use the computer but want to know why it has changed.