BIOS- Basic input/output system (WIKI
It is an IC on the motherboard that controls the board and peripheral components. Most computers use the method of repeatedly tapping the "Delete" key during the boot process to access the bios.
Your proprietary brand computers may (probably will) use a different key, you will need to refer to the manual for this (most manuals are available on the manufacturers website)
You do not need to enter the bios to set a master/slave configuration, this is done via a jumper on the rear of IDE drives.
EDIT: Mate basically this is all academic, you don't have an install disk to repair or reinstall his copy of ME so really we're just going around in circles as you can't do anything along the lines of reinstallation without a disk. (and no, your disk won't work on his pc)