Acer nitro 5 windows screen is not fitting perfectly into my laptop screen.

before a month i started facing these problem and in my laptop screen top part left unused as my window in nit using it and in bottom taskbar i am not able to see the which app are open and all the.i tried everything,which i found on internet hope someone from her can help me to resolve these issue as soon as possible .for my problem i am sharing photo.
as you can see in first photo the top part is cuutng on screen and showing black,and in second pic from bottom i have opened settings and amd settings but it also not showing like that they are opened .