UPDATE!! I borrowed a ti calc-to-calc cable and plugged it into a class calc. I took out a battery from mine and put it back in while holding delete. The install screen came up (jumbled), and on the class calc I selected send OS. After about 5 minutes of a jumbled "Receiving..." screen, the working calc said "Done" and mine turned off. When I turned it back on, it still didn't work!!! I heard there is a reset button near the backup battery, is that true?