CMOS RAM is Powered by a trickle of electricity from a small battery located on the motherboard or computer case, usually close to the firmware chip, so that when the computer is off, CMOS RAM still...
all motherboards have a series of small batteries or battery shaped in a circle most of the times,that can be removed manually and easily,that's why when you unplug your CPU your computer does not...
There is a battery on the motherboard. Generally speaking, it's a CR2032 3 Volt Button-cell battery. These batteries last quite some time and very rarely need replacement. Laptop's have them too, but...