How will preventing the inactivation of sodium channels affect the signaling capability of a neuron?

The neuron becomes more positive. This can lead to the neuron reaching threshold and then initiate an action potential. When the sodium channels are NOT functional, the sodium can not enter and depolarize it. Therefore the threshold can not be met and action potential will not occur. If the sodium channels are inactive in a nociceptive neuron (carries information about pain), then it will prevent you from feeling pain.