Hi everyone,   Thanks for all your help.  I deleted the Capt sim entry in the registry and then  full uninstall and reinstall of FSX and CS767 plus all my other add-ons.  I also defragged after I uninstalled FSX.  The problem is now fixed but  I don't what caused the problem in the first place.   I initially just reinstalled SP2 but that caused more problems.  I probably should have uninstalled it first or maybe I should have uninstalled and reinstalled both SP1 and SP2 first- Hmmm......  :-/      Could installing another add-on ( Like another B767 or a B757) cause this problem?  Also,  I believe from past experience that a repair of FSX usually results in having to reinstall all FSX add-ons anyway.  But next time This happens (Hopefully it does'nt.) I will try the steps mentioned  before a full smash.   Thanks again.   :) P.S. Mark,  I did find the kb# you mentioned but the steps were not successful but thanks anyway.