This can happen for a few reasons. It usually means that the registry hive or the graphics driver init file/settings are corrupted and cannot be updated, even though it "sets" it.
What I usually recommend is setting your driver to the standard SVGA or VGA, un-install your current video drivers, then rebooting and installing the drivers again, or download and install the latest version you can find.
I've seen this happen quite a few times, the above has fixed it(each one depended) each time.