Hi, im new here and i woul like some help since i cant find anything on the topic, i have a mid 2011 imac, i was running Sierra and i need an update because i cant have office or anything so i decided to buy a graphics card (k1100m) and try to update with dosdude patcher now i have a black screen and apparently something is working because if i hit a key on the keyboard it makes a sound but still black screen i decided to go back to the ATI graphics and it work with loads of graphical glitches, anybody know if i have to do something so it works with the nvidia card?