Right-click the folder > Properties > Security tab > select the username from the list > Permissions > clear the box labeled Read > OK
Open the folder > Tool > Folder Options > General tab > Read-only > OK
Open the Command Prompt > type attrib r [drive:][path] > Enter
Open the Command Prompt > type attrib +r [drive:][path] > Enter
Right-click the folder > Properties > General tab > Attributes > select Read-only > OK