Umberto will probably will have you check this link
http://www.fsdreamteam.com/forum/index.php/topic,10489.0.htmlI was having the same problem and had him check out my computer, and he seemed to fix it (at least temporarily). After he got it working and logged off TeamViewer, I tried fsx a little later and I was getting CTD once again. What I may do before I have Umberto get into my computer again is, I'll try making a backup of my FSX.cfg and have FSX build another .cfg and see if that will correct the problem. If not then I'll contact him again.
Umberto was working way to fast that could not see what he did to correct problem at first. Wish I looked more carefully so I could see if whatever it was that caused the problem was the problem once again or if the problem is something else.