You can download the latest OpenCV library from its sourceforge.net page. But for Windows 7, Windows Vista or Windows XP SP3 users, it is easy to download Latest OpenCV Windows executable (.exe) file and just double click it to install.
Once you have completed installing, you need to change some settings in your IDE so that it knows where to find the library files and header files of OpenCV. I’ll demonstrate the configuring process of Microsoft Visual Studio 2010. (The configuration process is same for Microsoft Visual C++ 2010 Express Edition (free))