FOR WINDOWS USERS ONLY! Step 1: Download your choice of N-Spire Student software here: (CX or CX CAS) TI-Nspire CX Student Software - Full Version, License Number Required for Activation (Windows and Macintosh)Guide How to get free TI N-Spire Student Software! (self.nspire). If you have, then delete your windows registry keys, uninstall, and follow this guide. This only works if you haven't already passed the trial version (30 days). Here are a few: This is how you will be able to get free computer software for your nspire forever. Looking on eBay, they seem to go from $40 to $80. Faced the same problem-bought the CX II CAS more than a year ago, but lost the license, maybe threw it in the trash by mistake level 1. If you need some sort of Ti-Nspire emulator for your computer without a license number, then it's technically possible but difficult to do.