sentry
Sentry enables you to quickly lock your your PC, so that nobody can access your desktop without the proper password. It offers a customizable lock screen that also includes an option to leave a message for you and can log all actions such as access attempts, incorrect passwords etc. Sentry includes a handy feature that allows you to export the program and settings to a USB stick, Floppy or CD to quickly lock any public workstation you may use while on the road.
Download from snapfiles here