A lot of computers allow you to pick a temporary start-up device. Usually your computer goes to the hard drive to start up, loading the operating system.
However in this case, since you want to boot from the CD to install a clean copy of Windows 7, you will need to boot to the CD drive instead.
Your BIOS must have the HDD ahead of the CD-ROM. You can try one of the methods below:
- When your computer boots up, tap the
F12 key a few times. If your BIOS supports it, it should bring up a menu to select a boot device. Using your arrow keys, highlight the
DVD drive entry and press enter. This will take you on your way to the Windows installation screen!
- Depending on your BIOS, you may need to press
F1, F2, DEL, ESC, F10, F11, or F12 to get to the BIOS setting screen.
- From here you will need to find a menu that resembles
Boot Order or
Boot Options or
Boot Devices or something of that nature
- When you enter the
Boot Order menu, move the
CD-ROM device to the top of the order list. This will cause your BIOS to attempt to boot from the CD before the HDD if possible
- Save & Quit, your machine will reboot with the new settings.
Hopefully this gets you going. If you provide the BIOS Make and Version number, or the type of computer you have (think brand here) I can make the instructions a bit more detailed.