Most computers are able to boot from devices other than your hard drive. In order to set your bios to boot from a cd, you will need to configure your bios to do so, of course. There are usually two keys that will get you into your bios. Right after your computer starts up, the computer performs a check of your system, it is at this time when you need to press either the DEL key or F1. You will be
. taken to the bios setup area where you can change the "Boot Device Priority" from your hard drive to your cd. There is a site, http://www.hiren.info/pages/bios-boot-cdrom, that offers a graphical illustration of exactly how to perform this task.