My computer checksum error

Hello,

My computer has a problem of CMOS checksum error,default loaded..The BIOS ca not read the drives.I already tried replacing cmos battery but still same error occur during boot-up.re-inserting the IDE cable did not solve the problem.I did shorting the pins to clear CMOS but still problem exist.I tried another memory card but still error.Another problem is that my keyboard has no function,just a tweeting sound came out when i beging to any button..what more should i do pls help..using WINDOS XP O.S.