After fixing what Best Buy’s Geek Patrol screwed up, ( don’t ever use them! ) I had to reinstall all my flight sim software, including steam.   

My favorite plane is the eagle soft Citation X.  Before my issues I was able to get up and flying with no problems, including using the auto pilot and auto nav.  

Now I can set up a flight plan, go through all the steps but after getting airborne, and activating the autopilot, it doesn’t track the waypoints and nav settings.  

Could someone please write the steps you use and may be it can help me see a step I’m missing?

also, my vnav  doesn’t work.  Any thoughts?

I have that aircraft but haven't used it in a while.  For now, have you tried the autopilot for the default aircraft?  If they don't work as well it is likely a FSX problem.  Try verifying the integrity of the files via Steam.  If you still get the same error, look up how to do a full reinstall.  This includes removing folders with your logbook, saved flights, saved settings, and so on.  I'd back them up rather than trash them and add back what you don't want to lose one by one after that full reinstall.

thanks  will do