If you already have Wings of Liberty installed on your computer, you do not need to install Heart of the Swarm from the game disk. Instead, start up the StarCraft II launcher and allow it to optimize your game files and download any pending updates. For assistance with patching or optimization, see our support articles:
If this is your first time installing StarCraft II, you can install the full game from the Heart of the Swarm game disk, which includes Wings of Liberty. A Wings of Liberty game license is required to play Heart of the Swarm.
Note: Before you can play Heart of the Swarm, you must add the game key to your Battle.net Account.