This post is for those individuals looking to see if this is possible… I just reset the BIOS on an HP Pavilion ZE4900 (laptop) by removing and replacing the CMOS battery. The online manual doesn’t show its location - but you need to complete disassemble the laptop down to removing the main board. The CMOS battery is located on the underside of the board toward the front of the laptop. Needless to say - the last four hours are hours I’ll never get back :-/