Boot Sentry is a security program that locks your computer so that no one can use it without knowing the password. It does this through two forms of protection: DOS Protection - Protects your computer at bootup, before windows start. Computer is locked out, and won't proceed with booting until the correct password is entered. If a wrong password is entered, a warning beep sounds ad nauseum. Windows Protection - Locks your computer after windows starts. You can also lock your computer at any time just by clicking the 'lock windows' icon in the Boot Sentry 3.0 Program group.