Most people think that the system clock in the computer always shows the correct date & time. But, that's not true. There are several situations where the system clock starts showing the wrong date & time.
If the computer clock loses time although you keep fixing it, there may be a serious cause. This article shows you what the underlying causes may be and how you can fix them.
This is the most likely scenario, especially if your computer is not brand new.
The CMOS battery sits on your computer’s motherboard and provides power to the Complementary Metal Oxide Semiconductor (CMOS) chip. The CMOS chip stores information about the system configuration, including the date and time. The CMOS battery makes sure the chip can store this data even while the computer is turned off and not hooked up to power. If the battery goes bad, the chip starts losing information and one of the symptoms is that your computer no longer maintains its time and date.
Replacing the CMOS battery is pretty easy. You just have to turn off your computer, ground yourself, open the case, find out which type of battery sits on your motherboard, go buy it, start over, and exchange the battery.
2. Time Zone
This is an easy to fix cause for when your computer clock loses time.
Your computer may simply be set to the wrong time zone and every time you fix the time, it resets itself to that time zone when you reboot.
In Windows 7 you can easily fix the time zone. Right-click the system clock in your taskbar and select > Adjust date/time. Under the "Time Zone" section, click the > Change time zone… button and set your time zone. Don’t forget to confirm your changes and you’re all set.