My taskbar isn't showing my taskbar and it won't even click

Hello,
My computer's taskbar isn't showing, won't click on anything and even when I use it on the keyboard my start button doesn't work. If I higher the volume the bar comes up but i have to click on it to scroll it but it was fine a few days ago, now I can't even use Cortana. Does anyone know what it happening and if you do please help me I tried another website but it wouldn't work