My 10z 1120 laptop has stopped extending to a second screen and resolution change drop down greyed out after a Windows update. Text became jagged. I deleted the display drivers and restarted. Text is no longer jagged but cannot change resolution (greyed out). I need the correct Dell card driver for Windows 8.1. How do I go about finding it? The service tag just shows a bios update available which I have performed. There is no driver pack. Thank you.