The boot menu is a menu accessible when a computer is first starting up. It can contain a number of different device options to boot to, including CD, DVD, Flash or hard drives, and a LAN (network). The boot menu allows a user to load up other operating systems or applications, even if the computer itself already has an operating system on it. It is also useful when trying to install a new operating system on a computer, and the user needs to load the installation application from a CD or DVD.
When a computer is starting up, the user can access the boot menu by pressing one of several keyboard keys. Common keys for accessing the boot menu are Esc, F2, F10 or F12, depending on the manufacturer of the computer or motherboard. The specific key to press is usually specified on the computer's startup screen. The boot menu allows a user to select what device to load an operating system or application from as the computer is booting.
If desired, the order of the devices listed in the boot menu, also called the boot sequence, can be changed, so that the computer always tries to boot to the hard drive or to a CD/DVD drive.