the game wont start

about a year back I changed some thing in the back area that it was saying I could change for the Graphix , but then it stopped working , I re-downloaded and have not been able for all this time to find out how to change , because it will not let me back in to change it back ... can you reset it to so i can play again please and thank you ... it keeps saying .. vk::createinstanceUnique:ErrorExtensionNotPresent ... please help i love the game and would like to play it again