Have you tried changing the boot sequence in system BIOS so that CD is your first boot device?
In most computers you press DEL key to enter BIOS when it starts.
Then somewhere is listed boot sequence or first boot device, second boot device etc.
After you have made changes save them (usually there is an option "Save and Exit") and restart your computer.
In some modern computers, you dont have to make permanent changes, during boot an option is shown to choose boot device (by pressing F12 usually).
All the key combinations vary from BIOS to BIOS. Observe carefully when you computer is booting up, what options you are shown.
If you have made the above changes, and still are not able to boot from the CD. Then possibly your CD drive is faulty or the CD is not bootable. To check the both cases, try booting using the same disk on other computers and you will find out.
Edited by Romeo29, 29 March 2009 - 08:00 PM.