Normally setting the Overscan to 0 resolves this issue. If it did not, it could indeed be an issue with your video card. Before upgrading your video card however, I would recommend you first check the system requirements for Nero 12 Platinum athttp/www.nero.com/enu/products/nero12-platinum/system-requriments.php.
If your system meets the minimum requirements, I would contact Tech Support, being sure to mention that you have already set the Overscan to 0, and give them a chance to troubleshoot your issue.
To contact Technical Support go to http/www.nero.com/enu/support/, select "Contact", then choose "Technical Questions".