Plug in your calculator with the USB charging cable. Open the free TI Connect CE app on your computer and drag both files into it.
Run the program
Press PRGM, select HWID, and press ENTER twice. It prints your Calculator ID on the screen.
Getting "ERROR: VALIDATION" or "SYNTAX"?
Some newer calculators need a quick, free compatibility step (arTIfiCE) before they can run custom programs. The 2-minute tutorial walks you through it.