Hi @ all,
I'm still actice.
Two questions - two answers.
1. BIOS chip: Usually there are SEEPROMs for BIOS on Board. SEEPROM=Serial Electrically Erasable Programmable Read Only Memory. They are used on newer Boards since about 2005. SEEPROMS on mainboards are manufactured by Macronix, Winbond, SST and a lot more. They have this syntax of name: 25..[size] i. e. MX25L1605 (Macronix=MX 16 MBit=2 MByte), W25Q80 (Winbond 8 MBit=1MByte). The name differs between the manufacturers, there is no unique name. It is a 8 pin chip and a little larger than these MOSFET switching Transistors in a 8 pin case.
2. C-MOS: The C-MOS is integrated in the RTC-Chip, as usual. On modern boards the RTC is a integrated controller chip with RAM and ROM. It is sensless searching for it... You can't change anything without a special program for programming that neither on nor off board. But resetting is still possible by removing (or short circuiting) the C-MOS battery.
Notebooks often don't start if the C-MOS battery is exhausted. Sometimes an exchange helps easily...
Some boards have no battery but a little soldered LiION-accumuilator - look at the description and then google it

. They also don't live forever...
I hope I could help a little bit.