If the BIOS does not locate the boot record in of the indicated drives, it will most likely display a "Non-System Disk," "Disk Error," or "ROM BASIC Interpreter Not Found" message on the screen.

The standard CMOS Setup screens from various BIOS manufacturers all provide the same basic information. For example, they can be used to set the date and time via the system clock/calendar.COMS, BIOS

The PnP device communicates with the BIOS during the initialization phase of the startup to tell the system what type of device it is, where it is located in the system, and what its resource needs are.

BIOS antivirus functions should be turned off when conducting an upgrade to the operating system. The built-in virus warning utility will check the drive's boot sector for changes. The changes that the new operating system will attempt to make to the boot sector will be interpreted as a virus, and the utility will act to prevent the upgrade from occurring.

When a parity error occurs, a Non-Maskable Interrupt (NMI) signal is co-generated in the system, causing the BIOS to execute its NMI handler routine. This routine will normally place a parity error message onscreen, along with an option to shut down the system or to continue. In other cases, the system will show a short memory count during the POST and lock up without an error message. Another possibility is that the system will count the memory, lock up, and reboot itself. If the memory error occurs higher in the physical memory device, this situation can occur after the operating system and applications have been loaded and started running.

If an 850MHz Pentium III processor were installed in a system whose BIOS only supported processor speeds up to 600MHz, the BIOS will only report a processor speed of 600MHz during the POST portion of the startup. The system will actually be limited to running at 600MHz.

The observable actions of a working system's cold-boot procedure are listed as follows, in their order of occurrence: 1) When power is applied, the power supply fan activates; 2) The keyboard lights flash as the rest of the system components are being reset; 3) A BIOS message displays on the monitor; 4) A memory test flickers on the monitor; 5) The floppy disk drive access light comes on briefly (if enabled in the CMOS boot sequence); 6) The hard disk drive access light comes on briefly; 7)The system beeps, indicating that it has completed its Power On Self Tests and initialization process. After this point, the operation of the machine has shifted to looking for and loading an operating system.

If you need to update the BIOS IC and it cannot be flashed or swapped, you will need to upgrade the entire system board.

When the system is upgraded, the BIOS should also be upgraded to support it. In newer system boards, this can be accomplished by flashing (electrically altering) the information in the BIOS with the latest compatibility firmware. Themost recent full non-beta version of the BIOS should be used for this upgrade.

If you install a new microprocessor in a system and the auto-detect function for the microprocessor does not work, you must make sure that 1) the BIOS version will support the new processor, and 2) the Core Voltage, Bus Frequency, and Bus Ratio settings are properly configured for the new processor.