CMOS Checksum Error

I am rebuilding an old Abit KR7A. The problem I have is, I can get into bios from a cold start, but after making changes and saving, I get the no post (black screen, no beep, flashing monitor signal). If I cold boot it, I get "cmos checksum error. press f1 to continue or del to enter". I have switched memory, and installed a new battery. The CPU is reported correctly, but when I get back into bios, it hasnt saved anything entered and is defaulted. I have also removed the battery for several minutes. Any other ideas?
Thanks

 

make sure the cmos reset jumper is set in right position.

 

Thanks bonkers, for your reply. I used the clear cmos, and the jumper is neutral.

 

I'm not sure if the problem has been solved, but put in a new CMOS battery. They're only $3 or so. The standard is a 3v CR2032. You can test yours with a multimeter. If it reads below 2.8v it should be replaced.