Bug/Issue PC Display Issues - Scrolling Not Smooth, But Shaky

Sometimes as I'm playing the game, the display (that is, the entire screen) is shaky/jerky and my character's movements are the same, like there's some kind of lag.

It occurs most often in the mines, though it can happen any time, any place, under any conditions in the game. It also happens in fits and starts - going from smooth scrolling and movement to shaky and back again. Constantly.

The game has never done this on this computer before, but I recently reinstalled it after having removed it previously. I use a Dell Inspirion 5759 with a 64 bit system and 16 GB of RAM. It runs Windows 10.

I also have not changed any settings recently that could affect computer performance, and I scanned today for viruses - nothing.

Any ideas? Thanks.