Look for ADD REMOVE PRO on google.com. Try it's uninstall, if that fails ask ADD REMOVE PRO to remove the item from the add/remove list. Now delete the Earthsim directory in "Program Files" and then the shortcuts and menu items.
That's a "manual uninstall."
I've tried the conventional uninstall method. Using a Compaq Presario 6470NX and running Windows XP Home. A download of some ATI thing was made on my desktop. I was able to uninstall 'Steam' which came with 'Earthsim', but, Earthsim will not be uninstalled. Please, clue me.