Did you install the CorelDRAW X7 shell extension when installing the program? The shell extension is required to view the CorelDRAW artwork thumbnails rather than just see green balloon icons. I'm not sure if there is any way to manually add the shell extension to an existing CorelDRAW X7 installation. You may have to uninstall the program and the re-install it, making sure the shell extension gets installed as part of the process.