I am new to security for PCs. We have a very small town public library. I need to find a way to secure the Internet. Let them use it as much as they want. Our main concern is to keep the homepage from being changed either by a user or some other program. I have founds ways to gray out the place where the user can make changes to the homepage. But, how do I keep the user from clicking "yes" if some site they visit asks them if they want to change the homepage? Thank you.