CMOS problem

I have a digital High Note CS450, when I try to boot into Windows95 I get the error, CMOS CHECKSUM INVALID -RUN SETUP, it does the memory check and then to enter SETUP, I can’t enter setup. Then Press F1 to continue, it prompts me for boot floppy, I have replaced CMOS battery and rebooted with same result. I can’t get into BIOS. What next? I have run set up, and reinstalled operating system, but still can’t boot into Win95, help???