My TI-84 Plus Silver Edition graphing calculator screen shows only a dark solid green. I have changed the batteries. What could be the problem?

Check and see whether both your Xscl and Yscl values are too small. If that’s what’s wrong, try pressing [WINDOW] and adjust the Xscl or Yscl or both.

Was it like this before you changed your batteries?

When my batteries are dying, I usually have to adjust the screen contrast. Once I change my batteries, the contrast is still set to the old, high level. Maybe you just have to adjust the screen down a bit?

I have an ancient TI-83, but I assume the contrast settings are about the same?

Your contrast could be way high.

Hold 2nd, and hit down on the pad multiple times and see if that helps.