How get block from Mario 64 ds?

Answer 1

After obtaining at least 10 stars go to the main hallway in the castle (the one you reach when you enter the castle). You will notice a spotlight on the center. Stand in the spotlight as Mario and look up at the source of the light. To activate free looking press the 'X' button. You will then enter a new area wearing a winged cap (if you're Mario. If you're not you'll just fall down). Fly to the center of the level where you'll see a big switch. Jump on the switch to unlock blocks.

Answer 2

You need 14 stars then look at the light from the roof in the castle