Rom bios checksum error

Thanks for the advice but I have already tried a new battery but that did not fix the problem. I have taken the new battery out and booted the computer to see what would happen and I still get the same message. I have disconnected one of my SATA drives and I still get the message. I am at a lose to understand why I keep getting the following message "Keyboard error or no keyboard present CMOS checksum error - Defaults loaded" Its very frustrating any other suggestions apart from replacing the battery will be much appreciated.

Kind Regards

Dr Syntax