Download and install the TI-Nspire Computer Link Software.

Go to TI's website and select your type of Nspire CX for the Technology box. Select 'connectivity software' for the View box.

Download the correct OS for your Nspire.

Go to TI's website and select your type of Nspire CX for the Technology box. Select 'Handheld Operating System' for the View box.

Connect your calculator to your computer via the USB A to mini USB B cable (the charging cable).

Launch the TI-Nspire Link Software on your computer. It should automatically detect your calculator.

Go to 'tools' in the top left hand corner and select 'install OS'. Select the OS you downloaded and the software will install it.