Deskman is a powerful commercial tool which provides a huge number of options to help you lock down and restrict a PC, very useful when for instance you're setting up a computer in a business or a school.
You can hide the regular Start menu, for instance, and create a Safe Menu which includes only the options you'd like users to run. You might then prevent all web browsing, or limit users to your choice of sites. While the ability to create a cut-down Task Manager with just a few options means technical users won't find easy ways to bypass your protection.
If you've created a custom desktop for your users, then Deskman can help you to preserve this, restricting changes to icons and restoring your preferred icon positions whenever it's activated.
And while of course there are plenty of other ways in which users might try to get around your restrictions, Deskman also has the tools to block them. So you can hide the system tray, for instance, or application buttons, maybe make the taskbar disappear entirely. You're able to disable a host of keyboard shortcuts (Alt+Tab, Alt+Esc, Ctrl+Alt+Del, Ctrl+Shift+Esc and many more). And the list goes on, with options to tweak Explorer, turn off AutoPlay, disable USB drives, hide particular (or all) hard drives, and more.
Setting this up can take a while, but that's just because there are so many options: the program isn't otherwise difficult to use. For the most part you'll just be working your way through a single dialog, checking boxes next to any restrictions you want to apply. And when you're finished, Deskman's security can be enabled with a click.
The program isn't cheap, then, but if you need to completely lock down a PC then we think it's worth the money. Deskman comes packed with useful functionality and it'll save you a great deal of time and hassle.