title: visual studio cannot open vcxproj after installing c# component
body: <p>I was happily using VS2010 Premium version for a C/C++ coding project, and needed to add the C# components (long, irrelevant explanation on that).  When I tried to go back and open up my existing C/C++ solution, i received the following VS2010 error: cannot open projectName.vcxproj because "it is not supported by this version of the application."  Any ideas ?</p>