ABC Security Protector is a nice free password protected security utility, which enables you to protect your PC by disabling some features like: use of the MS-DOS command prompt in Windows and real mode DOS applications from within the Windows shell, and disable function keys on boot up like the F5, F6 and F8 keys. The program is very useful if you want to disable the lowlevel access to your system. It's easy to use, reliably protected by the password and excellent online help is also available.....(free).....