I suggest that you check the information posted at this URL:
And check directly with your Original Equipment Manufacturer for further troubleshooting on this issue.
The menu Rotation and the option Enable Rotation simply do not exist in video options. However, today I had one more proof that my graphics card supports rotation, because when I installed Windows 8 rotation came enabled by default in generic driver. But updating the video driver to the latest the option to rotate ceased to exist again
Edit: when I uninstall the updated driver, returning to generic, the rotation back.