BIOS-The BIOS (Basic Input-Output System) or UEFI Unified Extensible Firmware Interface is a software located on the motherboard ROM chipset, which handles all the startup routines necessary to get the computer running.
CMOS - Stores around 64K of Programming Short for complementary metal oxide semiconductor. Pronounced see-moss, CMOS is a widely used type of semiconductor. CMOS semiconductors use both NMOS (negative polarity) and PMOS (positive polarity) circuits. Since only one of the circuit types is on at any given time, CMOS chips require less power than chips using just one type of transistor. This makes them particularly attractive for use in battery-powered devices, such as portable computers. Personal computers also contain a small amount of battery-powered CMOS memory to hold the date, time, and system setup parameters.
Note: some new motherboard designs allow access to the CMOS setup to be disabled through a motherboard jumper. If you cannot access the setup using the proper key commands stated above check your motherboard settings to see if the access has been disabled.
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