You can call me a liar if that make sit easier for you...
Nobody called you "a liar", of course.
Since all your previous descriptions of the problems were very vague,when you said you reinstalled Windows 3 times completely formatting your hard drive, I can only assume you meant something else, perhaps a single Windows reformat, and other "clean installs" (which weren't really "clean" for reasons I've already explained), like reinstalling FSX or something else.
Since the ONLY thing that can cause a loss of buildings in *default* sceneries it's the FSDT INSTALLER that was in some way tricked by an already-corrupted scenery.cfg in your system, this clearly proves it wasn't a reformatting, because you still had your old scenery.cfg.
So no, I'm NOT called you a liar, and you are very wrong believing so, but you simply meant something else when you said you reformatted 3 times (and besides, how about the Windows activation ? It surely doesn't allow 3 complete reformat in a short time), because the very fact the problem exists, clearly proves you still have leftover files from a previous installation that are causing the problem.
Of course, if the problem was caused by any of our products, you would imagine that at least SOMEONE else would have noticed it by now, considering KLAS has been released more than 2 years ago and KLAX about 1 year ago, and there are many thousands of users using them, most of them together, and NOBODY ever reported losing *default* buildings in any case.
Still not convinced ? Install Teamviewer
http://www.teamviewer.comSend me your session ID and password using Private Message, and I'll have a look at your system.