What is the exact model number of your system? But generally, yes that is the classic symptom of a bad CMOS battery. That battery is a CR2032 or Duracell DL2032. Make sure you leave the old battery out of the system for 15 minutes or so before installing the new battery.
Greetings I have a question. The date and time in the bios is incorrect.The problem is when enter the correct date and tim there is no option to apply the change is greyed out. There is no password in the bios and I have restored the default settings yet it It keeps reverting back to the same wrong date. Could it be the cmos battery that needs changing or is it some other problem? The bios revision is A24 thanks for the help.
Dell optiplex bios