One easy way of locking LAN connection properties is to use the built-in Windows Group Policy editor. You must log in using a username which has administration rights then using the Run command (Start > Run) enter gpedit.msc and a new window will pop up with policy options. What you need to configure resides under: User Configuration\Administrative Templates\Network\Network Connections. You need to double click on Prohibit access to properties of a LAN connection and from the window that opens, select Enable and then click ok. Upon logging in, the users will have the right removed regarding access properties of a LAN connection. You can see the specified option in the image below.