How do you defeat Voldemort in Harry Potter 5?

Harry Potter doesn't defeat Voldemort in Harry Potter and the Order of the Phoenix. That's the big tension of the book – Voldemort is back, powerful, and wreaking havoc, but Harry's struggle is mostly about his own personal growth, dealing with the Ministry's denial of Voldemort's return, and coping with the grief of Sirius's death.

While Harry does have a significant encounter with Voldemort in the Department of Mysteries, he doesn't actually defeat him. The battle ends in a stalemate, and the real victory comes from the power of love and friendship, which allows Dumbledore and the Order to escape.

Here's what happens:

* The Prophecy: Voldemort learns about the prophecy that says only someone able to "vanquish" him "has the power to vanquish the Dark Lord." This prophecy could apply to Harry or Neville.

* The Battle: Voldemort and Harry face off in the Department of Mysteries, leading to a chaotic fight that ultimately ends with neither side truly winning.

* The Power of Love: While Voldemort believes he has Harry defeated, Dumbledore and the Order of the Phoenix arrive and the power of their love and loyalty to Harry allows them to escape with him.

* The True Victory: The real victory for Harry is in the realization that he is not alone in his fight. This realization helps him grow and prepare for the bigger battles to come.

So, while the fight in the Department of Mysteries was a major confrontation, it's not where Harry actually defeats Voldemort. That comes later in the series.