Some MBs suggest that you change the battery with the power on so as not to loose the settings.
As I've been reading around this topic ('cos I have to actually change the battery on my laptop), I've got the impression that on most (all?) newer MOBO's, the BIOS data is stored in flash RAM, so the CMOS battery is only used for the RTC. Therefore BIOS settings should not be affected at all by removing the CMOS battery.
I haven't found a definition of "newer", though, so I'm not sure whether this means 5 years, 10 years or what! The laptop is about 7 years old, Compaq pre-HP purchase.
SD