please help have cmos checksum defaults loaded

[ichbin01]

I  had an amd Athlon  given to me I was told that the cmos battery had  gone when I was given it and after I got another drive to put in it . it wont boot past checksum defaults loaded , I understood this to mean the battery so I have replaced it but it still only goes as far as the same error message , it will not let me enter the bios  am I looking at major motherboard failure ? please anyone advise

[Geek-9pm]

Please provide model number of the main board, if you can. Or the model number of the computer.
Also, what is the exact error message?
One of these?

    BIOS ROM checksum error
    System CMOS checksum bad - default configuration used
    Press <F1> to resume, <F2> to Setup
    CMOS Checksum Bad
    Press F2 to Run SETUP
    Press F1 to load default values and continue
    CMOS Checksum Error - Default loaded

Often thee is some option to confirm and enter BIOS.