I have never had problem with windows for 2 years.It's simple to accuse windows.
According to the evidence YOU posted, the problem is not "Windows", but the VC++ 2005 runtime library, which has probably been corrupted by installing another product, even unrelated to Flight sim. It's known that a specific version of the *2008* library, corrupted the MSVCR80.DLL that came with the 2005, Microsoft has fixed this, but maybe you installed something that came with the bugged version. Can be anything, not necessarily an FSX addon.
I play with the last games without any problem
You can play everything that doesn't require the VC+2005 runtime library, "latest games" usually come with later version, so you won't notice any problem.
Never had problem with a FSX add on.
You don't have any problem with an FSX add-on, you have a problem with your VC++ 2005 runtime. MSCVR80.DLL is part of *that* library.
I will post in 5-6 month, i'm sure i won't have any problem with my computer.
You surely have, but maybe the problem will fix itself on the next Windows update.