You may need to reinstall your OS. Seems like OS corrupted. I would suggest that you refresh the OS on your laptop:
https://superuser.com/questions/714265/windows-8-1-text-showing-up-as-random-artifacts
https://www.computing.net/answers/windows-8/screen-display-symbols-instead-of-text-on-windows-8/2088.html
and lastly
https://newatlas.com/how-to-windows-8-pc-refresh-reset/32801/