Does your calculator actually turn on but the screen is broken? You can test this out by installing [https://education.ti.com/en/software/details/en/CA9C74CAD02440A69FDC7189D7E1B6C2/swticonnectcesoftware|TI Connect CE] and connecting your calculator to your computer. If TI Connect CE doesn’t recognize the calculator is connected, I’m sorry, but you’ll have to call TI support and try to get a new calculator.
If TI Connect CE recognizes that a calculator is connected, that means you have a broken screen. Unfortunately, I don’t think you can buy a replacement screen, however if you take the calculator apart, you may be able to finagle the ribbon cable which (in only the best circumstances) may make it work again.
You can try [https://youtu.be/8HlPgS0elRM?t=2m19s|reinstalling the OS], however I don’t believe that would help in this case. If you ever get your calculator working again, you can test if it’s because of defective RAM or ROM by running a self test. You can see how to use it [https://www.youtube.com/watch?v=G1PR43Ol9T8|here]; read the description for time-stamps and run tests 6 and 7.