Spoilers through Harry Potter and the Deathly Hallows Part 2.
The seven Horcruxes are the diary, the ring, Slytherin’s locket, Hufflepuff’s cup, Ravenclaw’s diadem, Nagini and the piece of Lord Voldemort (Ralph Fiennes) living inside Harry Potter (Daniel Radcliffe). Each one keeps Voldemort alive for as long as it survives. Beating him takes more than Harry winning a duel. Every surviving piece has to be destroyed.
Harry destroys Tom Riddle’s diary with a basilisk fang
Harry Potter and the Chamber of Secrets
Harry faces Tom Riddle beside Ginny in the Chamber of Secrets. Warner Bros. Pictures
Harry saves Ginny Weasley (Bonnie Wright) by stabbing the diary with a basilisk fang, with the basilisk’s poison already in him. Tom Riddle (Christian Coulson) has been using her to open the Chamber, and he spells out the cost himself: “You see, as poor Ginny grows weaker, I grow stronger.”
Harry destroys his first Horcrux four films before anyone tells him what a Horcrux is.
Dumbledore has already destroyed the ring
Harry Potter and the Half-Blood Prince
Albus Dumbledore (Michael Gambon) has two ruined Horcruxes in his office. One is the diary: “Four years ago, in the Chamber of Secrets, you brought me this.”
Harry asks, “And the ring?” Dumbledore’s answer: it “belonged to Voldemort’s mother. Difficult to find. Even more difficult to destroy.”
Harry never sees it done, and it is the only Horcrux destroyed off screen. By now Dumbledore’s hand is blackened by a curse, and where that curse came from is never said.
Ron destroys Slytherin’s locket with the Sword of Gryffindor
Harry Potter and the Deathly Hallows Part 1
Ron holds the Sword of Gryffindor beside the pool. Warner Bros. Pictures
Ron Weasley (Rupert Grint) walked out on Harry and Hermione Granger (Emma Watson) weeks earlier. He comes back in time to pull Harry out of a frozen pool, and destroys the locket with the sword Harry was diving for. Hermione has already worked out why the sword can do it: Harry stabbed the basilisk with it in his second year, and “Its blade is impregnated with basilisk venom.”
Before Ron can strike, the locket shows him a Harry and Hermione who say they were better off without him. Ron has to look at his own jealousy before he can bring the sword down.
Hermione destroys Hufflepuff’s cup with a basilisk fang
Harry Potter and the Deathly Hallows Part 2
Ron and Hermione face each other in the Chamber of Secrets. Warner Bros. Pictures
Hermione destroys the cup with a fang from the basilisk Harry killed in the Chamber of Secrets. Ron gets them into the Chamber by hissing in Parseltongue, and the only explanation offered is that “Harry talks in his sleep.”
Ron and Hermione kiss straight after.
Harry and Ron destroy Ravenclaw’s diadem in the burning room
Harry Potter and the Deathly Hallows Part 2
Gregory Goyle (Josh Herdman) sets the Room of Requirement on fire, and the fire gets away from him and kills him. Harry still turns back for Draco Malfoy (Tom Felton), with Ron right behind him: “If we die for them, Harry, I’m gonna kill you!”
Once they are out, Harry stabs the diadem with a basilisk fang and Ron kicks it back into the flames.
Voldemort destroys the piece of himself inside Harry
Harry Potter and the Deathly Hallows Part 2
Voldemort points his wand with Death Eaters behind him. Warner Bros. Pictures
The memories of Severus Snape (Alan Rickman) tell Harry what he is carrying. “A part of Voldemort lives inside him,” Dumbledore says of Harry, and Voldemort himself has to be the one to kill him. Harry walks into the forest and lets Voldemort hit him with the Killing Curse.
At King’s Cross, Harry asks whether part of Voldemort really lives in him. Dumbledore’s answer starts with one word, “Did.” The curse has destroyed it, “by none other than Voldemort himself”, and he adds, “You were the Horcrux he never meant to make, Harry.”
Voldemort finishes the job Harry could not do with a fang or a sword.
Neville destroys Nagini with the Sword of Gryffindor
Harry Potter and the Deathly Hallows Part 2
Neville holds the Sword of Gryffindor in the ruined courtyard. Warner Bros. Pictures
Neville Longbottom (Matthew Lewis) beheads Nagini with the Sword of Gryffindor as she goes for Ron and Hermione. She is the last Horcrux, and Neville’s blow leaves Voldemort mortal before the duel’s final exchange.
Five of the seven die by the basilisk from the Chamber, through its fangs or the venom in the sword, which makes Harry’s second year the quiet start of the whole hunt. By the final exchange, Harry is standing on work done by Ron, Hermione, Neville and Dumbledore, and on one mistake by Voldemort himself.