BIOS (basic input/output system) contains all the code required to control the keyboard, display screen, disk drives, serial communications, and a number of miscellaneous functions -- I just hope it didn't messed up your BIOS , 'coz then you would be unable even to boot
Thus you must be talking about CMOS (complementary metal oxide semiconductor) where all settings are stored date/time ,system setup parameters etc...)
Maybe is your battery running low on your motherboard and need to be replaced.
P.S. Do you have "Flash write Protect" enabled ?