Try the following to see if you can isolate the problem:
i). Start the laptop in safe mode with networking and check if the problem is still there. The display will appear different as only generic Windows drivers are installed and not the hardware specific drivers for the laptop model.
If the problem is no longer there then there is a driver problem. Check that the video drivers for the laptop are up to date.
ii). Connect an external monitor to the laptop and check if the problem is also seen on it. Even a TV can be used as an external monitor if you connect to it via the laptop’s HDMI port and you have an appropriate HDMI cable to connect the two together. Don’t forget to press the appropriate function key to switch the display between laptop only, external display only and both displays on together.
If the problem is also on the external monitor then there is a motherboard problem with the laptop.
iii). If the external monitor’s display is OK then it may be a problem with the LCD panel or less likely the video cable between the motherboard and the LCD panel. Here’s the maintenance and service guide for the laptop. Go to p.75 to view the necessary pre-requisite steps and then the procedure to remove the display assembly. This will allow you to check the video cable connections and also to replace the LCD panel if it is the problem as it cannot be repaired, it has to be replaced. Depending on your exact display variant (touch screen or non touch screen FHD or HD) the part number for the touch screen can be found at the top of p.75 and for the non touch screen panel there are two options, FHD or HD - see p.20 Item #8.
Search online using the appropriate to your exact model variant part number only to get results for suppliers that suit you best. Usually the part number can be found on the back of the LCD panel itself, if you wish to verify that you’re ordering the correct one.