cmos settings

unable to move around in cmos using arrows, nothing in cmos is highlighted except for hard drive, cd writer, cd rom, can not even change time/date as not highlighted, it is not the keyboard as can exit and save changes, this computer is a AMD AthlonXP1700, belongs to a 13year old girl who got into cmos and has done something, sytem will not boot into winxp and think it is because nothing is recognised in cmos except for drives. any ideas Thanks