|It *may* be the battery. Are you saying that the time changes "whenever it feels like it", or does something have to trigger the change? Like a reboot or when you restart it after being off overnight?|
Right click on the clock in the system tray, click "Adjust Date/Time", click on the "Internet Time" tab, then click "Update Now" (it may take a minute or so connect & make the change). Obviously that will correct the clock, now see if it stays that way.