TimeWatcher - description from Softdepia.com:
TimeWatcher Software allows you to set a time limit on the use of the computer. Enter a password and the amount of time you're going to let someone use your PC. When the time is up, TimeWatcher locks your desktop until you provide it with the proper password information.
TimeWatcher is an extremely useful tool for anyone who wants to control the access to a computer. It can help parents restrict the access to certain programs and folders and time their kids can spend at the computer. But the majority of the Internet-cafes, public libraries and hotels will also find it extremely beneficial and advantageous to control their customers' computer access. Besides the time controlling functions, TimeWatcher also offers the computer protection by the possibility to disable and restrict access to selected programs.
TimeWatcher can automatically launch at Startup menu, can provide custom logging support, and cannot be terminated with Ctrl-Alt-Del.
Download and buy TimeWatcher and you'll be able to control your employees, customers and children as well as instantly observe necessary security measures with no effort!
TimeWatcher is a "Free to try" program. You can download and try it for an evaluation period.