If a cable has jumped its drum or a torsion spring has let go, don't try to muscle the door up by hand and don't cut the second spring loose thinking you're making it safer - a torsion spring under load can break a wrist or worse, and on a door this old the spring winding cones may already be more worn than they look. That's not a job for a ladder and a Saturday afternoon.
What you can safely check yourself: whether the opener has power, whether the wall switch or remote is the actual point of failure rather than the door itself, and whether anything - a stored bin, a bike, ice buildup at the bottom seal in a cold stretch - is physically blocking the track. Elmhurst households sit at a median income of $145,374, well above the wider area's $96,794, and we mention that only because it means most of the doors we see out there were bought as a real investment, not the cheapest builder-grade option - which is one more reason not to force a repair on one yourself and risk cracking a panel that isn't cheap to replace.