Clock Changes Time

I have a problem with the computer clock changing time, always 1 hour earlier.
This occurs about every couple weeks and I simply correct it. Any idea what is happening and how to prevent it?

 

To check the easiest thing first, double click the time display, go to the Time Zone tab and make sure the correct time zone is selected.

If that's not it, another common cause of clock problems is a weak motherboard battery. It's located on the motherboard and looks like a large watch battery; about the size of a nickel.

They're not difficult to replace just tedious...takes a little fiddling to disengage the clip that holds it in. Just be sure the computer is turned off and unplugged before poking around inside the case, that you make note of which side is up before removing it and that you don't force it loose and break the clip. Take it with you to the store to make sure you get the right replacement.