diff --git a/README.md b/README.md
index b806b9585f08195c434de7f59270b1b821d7b728..1b854bf070bac42a887147592376d904192aacc1 100644
--- a/README.md
+++ b/README.md
@@ -137,8 +137,9 @@ Only compilation using Visual Studio 2010, 2012, and 2013 are supported.
   * If installing VS2010, make sure to install Service Pack 1, which fixes a linking error: <http://www.microsoft.com/en-us/download/details.aspx?id=23691>.
 
 2. Download and install the Qt 5.3 libraries for your version of Visual Studio from here: <http://download.qt-project.org/official_releases/qt/5.3/5.3.1>
+  * The Qt variant should be 32 bit (not 64) and include opengl. For Visual Studio 2013, this could be qt-opensource-windows-x86-msvc2013_opengl-5.3.1.exe for example.
 
-3. **[OPTIONAL]** Go to the QGroundControl folder and then to thirdParty/libxbee and build it following the instructions in win32.README
+3. **[OPTIONAL]** Go to the QGroundControl folder and then to libs/thirdParty/libxbee and build it following the instructions in win32.README.txt
 
 4. Open the Qt Command Prompt program from the Start Menu, navigate to the source folder of QGroundControl, and create the Visual Studio project by typing `qmake -tp vc qgroundcontrol.pro`
 
diff --git a/src/QGC.h b/src/QGC.h
index 6c822c176d62864a09de1ae5b11fd21d100deb28..f9b00845d1cdecff526273d13089c6b043a02260 100644
--- a/src/QGC.h
+++ b/src/QGC.h
@@ -33,13 +33,14 @@
 
 /* Windows fixes */
 #ifdef _MSC_VER
+#if (_MSC_VER < 1800)	/* only PRIOR to Visual Studio 2013 */
 /* Needed define for Eigen */
 //#define NOMINMAX
 #include <limits>
 template<typename T>
 inline bool isnan(T value)
 {
-    return value != value;
+	return value != value;
 
 }
 
@@ -47,8 +48,9 @@ inline bool isnan(T value)
 template<typename T>
 inline bool isinf(T value)
 {
-    return (value == std::numeric_limits<T>::infinity() || (-1*value) == std::numeric_limits<T>::infinity()) && std::numeric_limits<T>::has_infinity;
+	return (value == std::numeric_limits<T>::infinity() || (-1 * value) == std::numeric_limits<T>::infinity()) && std::numeric_limits<T>::has_infinity;
 }
+#endif
 #elif defined __APPLE__
 #include <cmath>
 #ifndef isnan