Keyboard Locking Software (Pref Free)

[Direwolf20]

Hey guys, heres a quick one for you.

I'm looking for software that will lock the keyboard and mouse, but not blank the screen or change it at all. The user can enter some kind of password or key combination to unlock it.

We're trying to setup one of those Kiosks at a mall, and want to have a PC there repeating a video about our company. If an interested party walks over, the person manning the Kiosk will be able to enter this special code to unlock the PC, give them a demo of a couple things, then restart the video and lock the keyboard/mouse again.

Does anyone know of some free, reliable software like this?

Thanks in advance!

P.S. I searched Yahoo, but didn't find anything specifically good. Either they cost money, or have flaws. One I found doesn't block Ctrl-Alt-Del.