what is this error when i boot my cusin portable it doest boot immediately error appears as" bad cmos battery -error date & time. it says there that i need to choose either f2 (utilities bios or press f1 .when press f2 it goes straight to bios of course! but the best option is to press f1 so it will bot normaly to the xp windows OS specs is WIN XP SP1. Do we need to replace the cmos battery now.