The Basic Input Output System - aka BIOS -resides in a small Flash EEPROM memory module on the motherboard. It's a form of read-only memory, but may be rewritten or programmed when the right tools and techniques are applied. During PC startup, the processor on the motherboard always executes the program stored in the BIOS as its first major maneuver.

When a PC dawdles through the boot process, the system runs slowly, Windows crashes, or the hardware fails, a badly configured BIOS may be at fault. In this article, we show you how to manipulate the switch center of your PC, to make your system run faster and work better.

The section entitled "Basics" covers BIOS fundamentals. There, you'll learn what a BIOS is, how you can access it, and how to find your way around it with confidence. The section entitled "Key Settings" explains important BIOS options about which every computer user should know. Advanced users may want to jump straight into the section entitled "BIOS Tuning"; there, they'll find out how to use hidden settings to activate unused power reserves, enable new functions, clear bottlenecks, and get rid of dead weight in the system.

Basics

As the first program executed by the processor at boot time, the BIOS introduces the CPU to the primary components on the motherboard, and instructs the CPU regarding which program to run next when the BIOS code has completed. As a rule, the BIOS then accesses the boot sector on the boot device, which might be a floppy disk, a CD-ROM, a DVD, or a hard disk. The boot sector in turn loads a boot manager program of some kind, which starts up the primary operating system for the machine, such as Windows or Linux.

After the start-up process ends, the BIOS still isn't finished with its chores. Many types of hardware access in a PC really involve the operating system accessing the BIOS, which then accesses the hardware on the operating system's behalf.