Hi Charles,
the problem is not the .Net Framework 4. When you create a plain C/C++ application, the standard is really that a plain win32 application is created.
But the binary format was changed and Windows XP does not support the new format.
What version of Visual Studio are you using? With 2010 a solution was to also add the older C/C++ compiler to create these files. If you use 2012 then you can simply tell the compiler to create a binary that also runs on Windows XP (Requires Update 1 so
please install it if you are missing it!).
If you tell us the version you are using, then I can give further information on what to do. (Sorry, I am to busy to lookup both right now.)
With kind regards,
Konrad