Hi,I've had the same problem before! First uninstall pmdg737-800 and -900 by using software remove. And than remove the 600/700. Shutdown the computer and startup again and shutdown again. After a new start. go with the explorer to the setup program of pmdg737 and execute it as adminstrator. Then the patch to 1.2 and after all the setup of the 800/900 again run as adminstrator and then the patches.Hope this will helpe youSuccess!Teun