Windows offers the option of running in a stripped-down environment called "Safe Mode." This gives users the ability to maintain and repair their operating systems, without running the software, driver or virus that needs to be removed or altered. But if you need to make alterations to Windows Vista's essential system files, booting into standard "Safe Mode" may not be enough. By booting into "Safe Mode with Command Prompt," you can make alterations to Vista while working outside of the operating system.
Restart your computer. Click on the "Start" button. Click on the arrow next to the lock icon in the "Start" menu. Select the "Restart" option from menu that pops up.
Press the "F8" key after your computer's boot sequence ends, but before the Windows Vista splash screen appears. You may need to tap the "F8" several times to ensure that you hit it at the right moment.
Use the arrow keys on your keyboard to select the "Safe Mode with Command Prompt" option, when the "Advanced Boot Options" menu appears. Press the "Enter" key to load the Command Prompt, or press "ESC" to boot into Vista normally.