With a lot of people having this same problem (read from past posts)
Only one or two, including you, still have it unsolved. Everybody else fixed it either by removing every VC++ 2005 files, repairing FSX, or reinstalling Windows. Have you tried that ?
I would think that the makers of this product would have found out what the files are. If we would be able to determine what files in VS++2005 bad, then we may be able to fix the problem.
If the solution was just "fix a missing file", it's fairly obvious we would have indicated quite clearly long ago. The issue is, is not a matter of a "missing" or "corrupted" file, that's just the short explanation because I can't type the complete explanation in a short post.
The real issue is, those libraries have a system that, if a program needs a specific version, your Windows will instead supply a newer one, if it's available, on the premise it's forward compatibile and it's "better". Sometimes this works, sometimes it doesn't and, if it wasn't already so complex, it's even possible to run two versions of the same library at the same time in memory, which wasn't possible with old-style .DLL (these are not plain .DLL but are Side-by-Side .DLLs a newer form) and this is also sometimes working and sometimes not. There were issues with the VC++ 2008 runtimes that created a problem if ran together with the 2005 ones, for example. Microsoft has fixed this, but you might still have this offending version installed by some other program, even not-flight sim related.
That's why I said it's usually easier to repair the FSX installation, because it's just too complex trying to diagnose what's wrong, when something doesn't work, the diagnostic tool for Side-by-side provided by Microsoft is so complex that I don't think anybody figured it out how to use it. If you add the fact these libraries comes with many additional support files AND are referenced in the registry too, you'll understand why it's not possible to give an universal "fix", but it must be dealt with case by case.
You don't have to take my word for this, see this post by Pete Dowson on Avsim:
http://forum.avsim.net/topic/323009-simconnect-gone-mad/page__p__1909995#entry1909995n my opinion the side-by-Side library system is the most diabolically convoluted system ever conceived and implemented by Microsoft and when it goes wrong it is fatal.
He's saying exactly the same thing: when something goes wrong related to WinSxS, it's almost impossible to fix it without reinstalling the whole OS. And the VC++ runtimes are of course SxS, like almost all Windows system libraries. This was a system created to fix the infamous "Dll hell", but it created an even worse one.