You may not find the icon settings, depending on the exact os version that you are running, with a right click in open field. You may need to open settings ... usual way ... windows icon then cog wheel. Then choose "Personalisation" > Themes. Then under the header Related Settings click on "Desktop icon settings"(may be in red text) The pop out menu will have a check box allow themes to change desktop icons. Whatever it is change the status and see whether that cures the problem. It is easy to put back to what is is now if it does not.