How to Lock Up Your Computer With a USB Drive

USB is a secure way to block Ophcracker from accessing your hard drive or password.  This will allow you to use a USB to BOOT to Windows.  If someone tries to start the computer without the USB(s) that you create, the screen will display boot errors. Warning: This may disable you from being able to boot into your Windows partition, please continue at your own risk.
You need:
-At least a 64MB or larger sized USB Stick
-Windows Recovery Disk (just in case)

--There are two ways to do this: with a program or manually
1. Use the program Predator which also allows you to remotely monitor all access-control activity on your PC

2. Or do this manually and show off your tech skills
        First make sure to "unhide" hidden and protected files, go to Tools > Options > View, check show hidden files and un-check Hide protected system files.
1.  From the hard drive where Windows is installed (usually the C:\ drive), copy the files boot.ini, ntdlr and ntdetect,com to the USB stick.
2.  Then go into BIOS, and enable the USB Drive as the first boot device (you may have to enable USB Legacy Support on older BIOSes).
3.  Restart the computer. If everything is correct, Windows will start up normally.  If not, unplug the USB Stick, return to the BIOS and change the First Boot device to the hard drive and repeat the first two steps above.
4.  Once logged into Windows, go to the hard drive where Windows is installed on and rename boot.ini to boot.bak.
5.  Now to test if everything was done correctly, eject the USB stick and reboot the computer, there should be a error message displayed on the screen, such as "Windows could not start" or "Invalid Boot.ini".

         Hope this helps
        -TerrabyteCafe