1.Download gnuplot. Current last version: 
  http://sourceforge.net/projects/gnuplot/files/gnuplot/4.4.4/gp444win32.zip/download 
  or check at 
  http://sourceforge.net/projects/gnuplot/files/gnuplot/.
2.Extract the files in the folder C:\Program Files\gnuplot. 
  It is important to have this folder since the Excel Add-in will look into it to get the executable.
3.Download QIPGraph.zip and extract all files in the folder C:\Program Files\QIPGraph.
4.Open Excel and install the add-in using Tool  Add-Ins  Browse to load the file 
  C:\Program Files\QIPGraph\ QIPGraphGUI.xla.    
5.C++ interface: The header files, .lib, and .dll are in the directory C:\Program Files\QIPGraph. 
  There are no dependencies to any other library apart STL. 
