Ok, so just got my brand new imac 2011 which I have had on order for some time. Been spending some time installing some apps. Starting to have a really weird problem now where my finder window, apple window and menu links will all appear black. http://i51.tinypic.com/2q023hl.png Done a few of the tests which are not coming up with any hardware faults. Restarted and shut down which will not fix this problem.... any ideas guys?