It's not the game! The fault seems to be hardware or BIOS related, possibly the new GFX card.
After exiting Windows (but not switching the PSU off) and then later boot my PC, the moniotor does not display anything. I doubt its the GFX driver because it isn't active untill Windows loads. If I do a soft re-set the display works during the re- boot but CloD runs very badly and the sound is a total mess.
But, if I exit windows -switch the PSU Off then re-boot its fine and CloD runs perfect. It's happened a few times now......