If you are seeing something on the screen from the CD, you are already past POST.
Take out the CD, and turn on the power, if you see an image of a company logo or plain text on the screen, hit the delete button repeatedly until it goes into the BIOS.
From BIOS, you'd have to change the booting sequence to the CD-rom drive first, then save and exit. It'll reboot itself again and start booting from the CD and you can install the OS then.
You won't hear any beep sound if the mobo does not have on-board speaker, or if you didn't install one yourself. Most mobos today don't have on-board speaker that gives off the beep sound.