Now i try to install openCV In windows by Using the Pre-built Libraries i want to Set the OpenCV enviroment variable and add it to the systems path but when i write :setx -m OPENCV_DIR D:\OpenCV\Build\x86\vc10 it tell me "'setx-m' n'est pas reconnu en tant que commande interne ou externe, un programme exécutable ou un fichier de commandes" can you help me please