Does the laptop's 'clock' advance if you change the time setting so that it does not synchronize with the internet time i.e keeps its' own time?
Check that the Windows Time service is set to Automatic and that it has started.
Type services.msc in the Windows search box, (then select services.msc). When the Services window opens scroll down to find the Windows Time entry. Verify that its' Startup Status is set to Automatic and that its' Status is Started.
If this is not the case, right click on the Windows Time entry and select Properties. Change the Startup Type to Automatic and Start the service in Service Status then click Apply
I think that you have a flat (no pun intended) CMOS/RTC battery in the laptop. This is usually a coin cell type battery (non-rechargeable) that maintains the BIOS settings and the clock settings when the laptop is turned off. They usually have a life span of 5-7 years.
Here is a link to a video which shows how to dis-assemble the laptop. At 6.21 minutes into the video the battery is visible (I think - I don't know your particular laptop but it looks like a coin cell battery to me, I've indicated it in this image
(click on image to enlarge for better viewing).
The coin cell battery type is stamped on the battery itself and usually is a commonly available type. Also ensure that you put the new one back in the correct way. Take a picture of the old one in situ before you take it out as a reference.