How come Google earth loads but the earth does not appear?

I've been using Google Earth for years. Suddenly (a couple of months ago) when I tried to use it, the application started up but the earth would not appear. I rebooted the computer and tried again. Same problem. Rebooted again and this time the application would not even open. I tried reinstalling the program. The application opened and the earth appeared but started zooming in and out by itself and acting weird, and there was no text in the menu. Finally I was able to take control and try to zoom in to a location but everything is blurry and will not come into focus. I cannot figure out what is wrong that this should start happening. Yes I did all of the updates and cleared all cookies and caches and viruses yada yada yada.