Hello
The BIOS is a special type of software stored on a non-volatile ROM chip on the motherboard, and is the first software run by a PC when powered on. The fundamental purposes of the BIOS is to initialize and test the system hardware components, and to load an operating system or other programs from a storage device (Hard disk, CD/DVD, USB etc).
http://www.howstuffworks.com/bios.htm
Since it is the responsibility of BIOS to scan for any bootable media from which an operating system can be loaded , modern BIOS vendors have provided us with various options so a user can decide which storage device to use when booting up a system. In your case if you want to boot from a CD you must enter the BIOS configuration screen via F12 and select from the options available, normally it is the hard disk but your case it's a CD, also there may be an option in the BIOS (usually on the boot device selection screen) to set the default boot device so the system will automatically boot from it without any user intervention.
Regarding your question do you want to install SuSE? or do you want to format the whole system?
PS-- the BIOS exists independent of any operating system on the computer (i.e. there is no thing as a Windows BIOS or a Linux BIOS, even if have no OS installed on the Hard disk the BIOS will still exist as it is literally "burned" on a chip)
