Why doesn't the clock on my laptop stay set?

You may need to change your CMOS battery if your computer clock isn't accurate when you boot. Like any battery the computer CMOS battery can fail or lose its charge. All computers require a small battery on the system board that provides power to the Complementary Metal Oxide Semiconductor (CMOS) chip, even while the computer is turned off. This chip contains information about the system configuration (e.g., hard disk type, floppy drive types, date and time, and the order in which the computer will look for bootable disks). The CMOS battery preserve these settings. Before you replace your CMOS battery It is important to get into the BIOS settings and write down any special settings. If you remove and replace the battery quick enough, you might not lose your settings, but it's best to write everything down. You can also use a Clock Synchronization software to update your clock automatically base on your time zone.

are you turn on your automatic update of your time?so it's fix automatically if you connect the internet?and your time setting didn't based your time area? Try to turn off your automatically time update, or windows time service, then correct your clock time

Check your timezone setting and ensure that it is set to your nearest location or probably there is an application running in your task notification area that set it to something else. A bad battery in your motherboard maybe causing it too but I have experience it does not reset the time as long as my PC is running, only when I boot up.