Those that meet ALL of the following criteria need to read the Update Fix Instructions and should NOT reboot their PC:

1. You started downloading the upgrade from Trinity Classic Graphics Content to Premium Graphics Content BEFORE 04:00 GMT on Dec 6
2. You must be using a version of Windows other than Vista.
3. You must have Windows installed not on the primary partition.
4. You must have at least 2 hard disks and the OS must be installed not on the primary, but the secondary hard disk

If all these apply, you MAY be affected by a known problem with the Graphics Update system.