Remove password from Word documents

Question

HI!!!

I am using this code to remove password from word documents

http://ishwor.cyberbudsonline.com/2013/01/remove-writeedit-protectionenforcement.html?showComment=1374659141159#c1604586394111748506
also this :

http://www.c-sharpcorner.com/Forums/Thread/61822/

the code works correctly and it opens documents when I am running but when I open ducuments again it asks me password .... I want remove the password for all ..... Please help me