Try to remove the main battery and power cord for few minutes and then check the time and date on the BIOS
You can also try to remove the main battery, the charger, and the bios time battery at the same time and then put them back and re-set BIOS settings.
You can also try to remove the main battery, the charger, and the bios time battery at the same time and then put them back and re-set BIOS settings.