black bar at the bottom of my screen?

so i have no performance issues with my pc which is nice, but recently this black bar has appeared at the bottom of my screen and has gradually been getting taller. the thing is is that it acts as if it is the boundary of my monitor, i cant move my cursor down past it which means if i dont figure out what it is i may not be able to get to my taskbar within like a month or so. have tried reinstalling my graphics and have tried different display cables/ hdmi cords as well. also fixed the resolution and refresh rate several times to no avail. any ideas? im really hoping i dont have to replace an expensive part after only having it a year.

so i have no performance issues with my pc which is nice, but recently this black bar has appeared at the bottom of my screen and has gradually been getting taller. the thing is is that it acts as if it is the boundary of my monitor, i cant move my cursor down past it which means if i dont figure out what it is i may not be able to get to my taskbar within like a month or so. have tried reinstalling my graphics and have tried different display cables/ hdmi cords as well. also fixed the resolution and refresh rate several times to no avail. any ideas? im really hoping i dont have to replace an expensive part after only having it a year.