TI calculators have an annoying habit of dimming the screen when the batteries are changed so that it appears as if the calculator isn't turning on. Turn the calculator on (or at least press the ON key). Press and release the 2ND key. Press and hold the Up-arrow key for a few seconds and see whether the screen becomes legible.
If that doesn't do anything, append a comment to this post and we'll go on to the next step.
Answers & Comments
TI calculators have an annoying habit of dimming the screen when the batteries are changed so that it appears as if the calculator isn't turning on. Turn the calculator on (or at least press the ON key). Press and release the 2ND key. Press and hold the Up-arrow key for a few seconds and see whether the screen becomes legible.
If that doesn't do anything, append a comment to this post and we'll go on to the next step.
So I take it that you're not interested in going on to the next step?