Upgrading PT 10 to PT11 HD

Hi, I would like some help in regards to Pro Tools 10 native on windows and I would like to upgrade to PT 11 HD native from PT 10 which is not HD. My question is do I need to uninstall everything PT 10 on my PC before installing new SW and which part of the old files(current song files and so forte) for the new SW so that I can recall them back on to the new Pro Tools 11 HD. Can I also use my same ilock key when I purchase the new PT 11 HD or do I need a new key from Avid, if so what will happen to the old key?