Do I have to de authorise my old pc now I have successfully installed Norton on my new laptop?

I have recently bought a new laptop and have managed to download Norton on to it.  I am selling my old pc and want to remove Norton from it.  Do i just remove the programme or do I have to de activate/de authorise my old pc first?  Will I lose one of my 3 available PCs on my Norton subscription?  Please help!!

 

Thanks