It depends. I'll try to be vague here to avoid spoilers for you and others.
The broken box can't be opened.
Opening the silver box only has a purpose at a certain time and place.
It doesn't have a purpose until you've experienced the memories (which may help you learn its purpose).
If you get too stuck, you can click the (?) button next to the input field. If you scroll to the bottom there's a link to a walkthrough with all the instructions for how to get the "best ending".