this is what the battery on your motherboard is for. Also as long as you are connected to wifi, then it will sync your computer time with the current timezone you are in.
If this is a Mac, it's a common problem and there isn't anything to fix it because it's just like that. I reccomend unplugging the computer and NOT signing off. Because of that, that may be why it is the problem for you. I do not know about Windows Computers, but this is some info that applies with all computers.
