Sometimes in the past my PC whilst driving in AC either online or offline and usually just once:- After a few minutes the screen goes blank for a few seconds then returns back to normal. Never when in the Ui menus. This effect only occurs once, then all is okay. This time online the screen went blank permanently and the steering stuck at 45° , but AC still running and Ui still working after pressing escape. ( had to turn steering wheel off and on to get it to work again.) Before I download an update ntdll.dll and replace it, because it showed up in the event viewer and associated it with AC program, has anyone any advice !