I pre-bought the game a while ago, I pre-downloaded it. Kept running the updates.

Then tonight, I try installing it and it says Disc is not in the drive, make sure it is in it? Then I search about this error and I see re-click on download it will fix it.

Alright, so I go to my D3 account, I click on download client, and I am redirected to Starcraft 2 download page.. Tried it 3 times and always bringing me to S2. Never bought or played this game. What is the problem and how can I fix it?