Why do I get a black screen when I turn on my TI-Nspire CAS?

Hi, when I turn on my TI-nspire CAS calculator it shows a full black screen. I have replaced the batteries, pushed the re-set button on the back, updated the software to 3.9.0.463 and still nothing happenes. The calculator works fine as when I do a "screen capture" from when it's connected to the computer, I can see what is on the calulator screen.