To fix ISO capability issue please follow these steps:
You need to manually choose the reset option in the Shooting Menu and the Setup menu. To do this press 'Menu', select the Shooting Menu and scroll through the options until 'Reset Shooting Options' is highlighted, press ok, highlight 'Yes' and press ok again. Repeat this for the Setup menu.If this method works, then its ok otherwise check Nikon D80 Manual for help.