TI-84 Plus silver edition calculator is messed up! HELP!?

I went to to use my graphing calculator and something is messed up. some of the buttons are not working and some of the numbers are just showing up as asterisk's. It want let me clear the screen, or second quit. I turned on and off the calculator as well and it still isn't working. I just changed the batteries like a month or two ago could I need new batteries? PLEASE HELP IN NEED IT TO WORK FOR THE ACT IN 3 DAYS!!!!!!!!