Desktop Locker

I need a Desktop Locker. What it basically does is it locks the desktop of a PC with a HTML PAGE/php script of your choice. It's exactly like a CONTENT LOCKER if you've heard of something like that, the difference is that it doesn't lock a page inside the browser, but the desktop. It has to be an executable, and when you double-click it, it will lock your desktop with a HTML PAGE/php script. Let me know if something like this is possible and the price could be raised substantially! Thank you.