I am attempting to connect an external display to my early 2011 cMBP pro. I purchased a Cirago branded (not Apple) mini displayport to DVI single link adapter. I tried connecting two monitors through the mini displayport adapter, one with a DVI cable and the other with a VGA cable with VGA/DVI adapter. Nothing appeared on either monitor and the arrangement tab in system preferences>display did not appear. I attempted pressing and holding F5, F6, & F7 and closing the lid but nothing happened. Any thoughts on how I can get an external display to work?