Which distribution of Linux do you use? Different bootloaders in different distributions. If it boots to windows that means you did not install the Linux bootloader to the master boot record and have not configured the windows bootloader to boot Linux. Boot your Linux installation CD and open a terminal and run the command: fdisk -l(Lower case Letter L in the command) You will need to do this as root user which can be done by entering: su - in a terminal. If you are using Ubuntu or one of its derivatives, prefix the command with: sudo
Posting the above info should give information which will help you to enable booting both systems.
Last edited by yancek; 07-17-2012 at 09:16 AM.