I have just fitted a new graphics card ATI HD 6670 , performance great , now from time to time the system crashes with DISPLAY DRIVER STOPPED RESPONDING BUT HAS RECOVERED , installed latest driver with no improvement , then did google search and found it to be a common issue with ATI cards , does anyone know the fix , I am running Windows 7 - 64 bit , previous card was Nvidia GT210 , had no issues with that one , please help