Predator is a Windows app that lets you use a thumb drive as a key that will instantly lock and unlock your computer. When you unplug the usb drive, your computer will automatically lock itself up. It also plays an alarm if any intruder enters the wrong password when they try to unlock it. When you plug it back in, your computer will go back to exactly the way you left it, no password typing necessary. You can still enter the password, in case you lost the usb.