Stuck in the Eighties

You are in the middle of moving into your dream house. While unpacking boxes, you find your high school time capsule from 1989 tucked away in a box. You decide you can't continue unpacking until you take a trip down memory lane. You find your old mix tapes, notes, and maybe a few photographs.
You open the lid, and immediately you are transported to December 31, 1989. Upon arriving back in time, a mysterious man with a mullet hands you a locked box and tells you that the key for the time capsule is inside if you can crack the code before the 1990s begin! 
Will you manage to make it back to the present day, or will you be forced to relive the 90s again.

While you're trying to figure out what is a clue and what is a the Safety Dance!