FLOPPY DISK DRIVE

I AM HAVING TROUBLE GETTING MY BOOT DISK TO SET UP ON MY A: DRIVE. I HAVE BOTH A CD-ROM AND A CD-RW DRIVE THAT FOR SOME REASON HAS DISAPPEARED FROM MY HARD DRIVE FILES. I CANNOT REBOOT MY COMPUTER WITH MY MASTER CD AS THE COMPUTER DOES NOT SHOW THAT I HAVE A CD DRIVE INSTALLED. I NEED HELP?????