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.