My screen started shaking... Is it going to kick the bucket?

Well I have a refurbished 17-inch Dell monitor I got for $50 about three years ago. It has held up pretty well, but now I fear it's starting to die on me. Just recently (as in the last few days) the screen started acting strange. Like it would move to the side for a second or two. The actual settings are the same as before. It's at its reccomended 1024 by 768 at 85 hz. It was fine until a few days ago. I updated my video drivers just in case but no change. Any help?