I installed VS2013 and VS2015 on Windows 7.
I have an existing C ++ Dll project that was building fine, but now it suddenly doesn’t use it with VS2015 and gives me an error:
LINK : fatal error LNK1104: cannot open file 'kernel32.lib'
From this post: fatal error LNK1104: cannot open file 'kernel32.lib' I searched for file kernel32.lib and is located here:
C:\Program Files (x86)\Windows Kits\8.1\Lib\winv6.3\um\x86
When I go to my projects Properties → Linker → Input and select Macros, I see that this path really is:

My Platform Toolset is installed in Visual Studio 2013 - Windows XP (v120_xp) , to which it has always been installed.
Why did my project suddenly stop building? What could have gone wrong?