I would suggest trying Fedora Core 12 Live CD instead of Linux Mint.
To help with what you are working on, it would be good to figure out what you need help with. It sounds to me like you have not completed the installation process, as you have yet to boot up after the installation was finished...it usually needs to complete the installation by booting up and configuring items.
You need to have a bootloader on your system. GRUB is a decent bootloader. You can create a GRUB boot CD too and boot from that if you would like.
There is no problem having GRUB in the MBR. That is how most people run Linux. The BIOS boot option should allow you to select to boot from CD and boot from a BOOTABLE CD. If it does not, then there could be a BIOS problem.
Linux Mint has a forum. I would try to get help from them, as they are Linux Mint users and developers!
Post any error messages that you get. That will help. And when you tell what hardware you have, give more details such as the manufacturer and model as opposed to just 1 TB Hitachi and CRT monitor. That can help too.