if your CV boot has been broken for a while then the joint is most likely dry of grease. Take it off and clean it before putting it back on, it will be full of grit most likely. Check if it is okay at this point, might be best to replace it as Shero said.
I found when I did mine I had to get a genuine nissan one because the little clip thing (forgot the name) that comes on the original one was broken and doesn't come with the none Nissan ones.