The motherboard on your computer contains a small program called the BIOS that manages connected hardware components and some low-level operations such as drive boot order. The BIOS works even when no operating system is installed and performs the Power-On Self Test each time you turn on your computer. The system POST uses a combination of screen output and beep codes to inform you of any problems at startup.
Processor
· Some computers beep once at startup to indicate a central processing unit failure. You can identify a faulty CPU as the cause of one beep if your computer has an AS