Try to reset the BIOS. Disconnect the charger and take the battery out. Press the power button for about a minute, reinstall the battery and see if the problem is solved.
If the problem is still there disconnect the charger and battery again. The next step is to search for the CMOS battery and take it out for 10 minutes. The battery looks like wrist watch battery but may be bigger. When it comes to laptops, every manufacturer puts the battery in a different place. Sometimes it's very simple to find, sometimes you have to take the laptop apart. Please open the covers at the bottom of the laptop and search for the battery. If you find it take it out carefully for 10 minutes, reinstall, reboot and set time and date when asked to do so.
Be careful with what you are doing. Do not apply unnecessary force. If the battery is not found under any of the easy-to-remove covers, then I suggest that you do not continue by yourself and look for a professional help.