Remove all of the AAA batteries from your calculator and press "On" for 30 seconds.
Insert the batteries and turn on the calculator by pressing "On."
Adjust your contrast after the calculator comes on by pressing and releasing the "2nd" button. Press the up or down arrow to make the contrast darker or lighter.
Remove the AAA batteries as well as the lithium battery for five minutes.
Replace all of the batteries and press "On."
Adjust your contrast if by pressing and releasing the "2nd" button. Press the up or down arrow to make the contrast darker or lighter.
Attach your calculator's connectivity cable to the computer and calculator. Take out one of the AAA batteries.
Press and hold the "DEL" button while reinserting the battery. Press "On" to turn the calculator back on.
Follow the directions on the screen to reinstall the calculator's operating system.