My calculator will turn on but when i press the buttons none of numbers show up on the screen and the calculator won't turn off

SOURCE: None of the buttons on my TI-84 Plus calculator are working.

is the cursor the graphing cursor or the normal typing cursor?

SOURCE: only the on button and shade of screen works

welll what i recommend you to do is to open your call culator
this will help it fix any problems that it has
Also clean all the ends of your calculator and check all the circuits
now this will only help you if you do a slow and patient proces otherwise you will mestup your calculator

SOURCE: garbage collecting

take out the batteries so it turns off then put them back in and hold down clear then press on

SOURCE: New batteries, does not stay on and is unresponsive

I had the exactly same problem, and my TI 84 plus used to be extremely unresponsive and slow, as I have been fixing the latter problem by blowing really hard into the I/O plot, I did the same to fix the new problem. For many times not thing happened though. Then I insert a metal stick into it and gently hit the inside. In a short time, the calc was normal again!! Now my calc even turns on when it's been put off, with its cursor frozen. I simply use my little finger to dig/scratch the plot and see the lovely cursor beating again.

SOURCE: my calculator started malfuctioning and it would

After you replace batteries, the screen contrast may become too light or to dark. In your case, I suspect it lightened too much.

To darken screen

Press [2nd] key and release it.
Press and HOLD the [UpArrow]
Keep pressing the Arrow key until screen darkens to your liking.

If that does not solve your problem search this website: I have answered countless number of questions on the same subject.