diff --git a/Doxygen/Developer/building.docu b/Doxygen/Developer/building.docu
index fecef6505c76015c4d476d38bb5e91b536d3b440..256fb3f694c79bbcd8bca0082c3ceef97a420ce3 100644
--- a/Doxygen/Developer/building.docu
+++ b/Doxygen/Developer/building.docu
@@ -54,7 +54,23 @@
  * <ul>
  * <li> Get Visual Studio >= 2008 </li>
  * <li> Get and Install Qt ( >= 4.5 , Visual Studio Version ) </li>
- * <li> Set the QTDIR Variable to your Qt Installation directory </li>
+ * <li> Set the QTDIR Variable to your Qt Installation directory:<br />
+ *      <b>Windows Vista/7:</b> <br />
+ *      Open the Control Panel<br />
+ *      Select System and Security -> System -> Advanced System settings<br />
+ *      Click on "Advanced" tab<br />
+ *      At the bottom click on "Environment Variables"<br />
+ *      In the bottom window,check if there is already a QTDIR entry and modify it or use "Add" to create it<br />
+ *      Set the path to your QT installation directory<br />
+ *<br />
+ *      <b>Windows XP:</b> <br />
+ *      Open the Control Panel<br />
+ *      Select System<br />
+ *      Click on "Advanced" tab<br />
+ *      At the bottom click on "Environment Variables"<br />
+ *      In the bottom window,check if there is already a QTDIR entry and modify it or use "Add" to create it<br />
+ *      Set the path to your QT installation directory<br />
+ *</li>
  * <li> Extract OpenFlipper source code. ( If you want to use svn  you can get a free svn client from http://tortoisesvn.net/downloads ) </li>
  * <li> Download the glew library and install it (The best way is to install it to c:\\libs\\glew directory ).)<br />
         The c:\\libs\\glew\\lib subdirectory should contain the dll and the *.lib files)<br />