during the boot process, the bios initializes your hardware, then passes off the boot process to a list of devices...floppy, cdrom, or hardrive (even a network card at times).
The order in which you bios tries to boot is listed somewhere in the bios setup screens.
During boot, does your pc flash Press F1 or Del or ins to enter setup, prior to seeing your boot screen you posted? If so, hit that key, search the menu's for "boot order" and make sure the your cdrom is before your harddrive....save then exit.
Then, on the next boot, your bios will try to hand off booting an OS to the cdrom. If it works, your all set, if not, then the bios will try handing off to the next boot device on its list, your harddrive.