I was running AutoCAD 2013 on OS 9.  But today when I started Autocad it said that there was an update and I installed it and Autocad stoped working.  Read that the update was for Yosemite so I though maybe I had to upgade my OS.  Next I installed OS X Yosemite and it still does not work.  

Downloaded SP3 and tried to install but it says that I need to install SP2.  But when I try to install SP it says:

"Operating System not up-to-date This version for AutoCAD 2013 for Mac requires OS X 10.6.4 or later."

How do I fix this?

Thank you