As the computer starts, watch the bottom of the screen for a prompt that tells you how to access the BIOS.
Generally, you must press Delete, F1, F2, or F10.
On the BIOS screen, select the Boot menu.
(The term boot refers to the location where the software that is required to start a computer is stored.)
Change the CD drive or DVD drive to be the first boot device in the list.
Save the changes and exit the BIOS setup. When you start your computer with the product CD in the drive, you see the prompt "press any key to boot from CD." If you do not press a key, your computer attempts to start from the next boot device that is listed in the BIOS. The prompt to press a key is displayed only briefly, so you need to watch carefully as the computer starts.
Press any key to start the computer from Windows 7 installation disk.