How did Harry Potter save Ginny Weasley's life in the Chamber of Secrets?

Answer 1

They resolve the conflict when Harry and Ron go to see Prof. Lockhart and they force Lockhart down into the chamber with them, there is a cave in, and Harry and Ron and Lockhart are separated. Then Harry goes to save Ginny, but meets a memory of Tom Riddle (Lord Voldemort's name before he was Lord Voldemort), fights him and the Basilisk (with help from Fawkes the Phoenix) and destroys Riddle's diary ( the diary Harry was writing in earlier in the novel) and destroys what's left of Riddle in that diary, freeing Ginny, then Fawkes carries them out of the Chamber, and there is the feast, Griffindor wins the cup. Everyone is happy again.

Answer 2

Harry Potter went down to the Chamber of Secrets. Once he got there he defeated the giant basilisk. Upon defeating the huge beast, he cut out one of its fangs and jammed it into Tom Riddle's diary. Once Harry did this, Tom Riddle went away. This in turn rescued Ginny whom was under a spell.

The stabbing of the diary helped Ginny and made Voldemort become less of a human because the diary was a horcrux, a part of Voldemort's soul. In the chamber, Tom Riddle was using the diary to drain life out of Ginny and Store it in the horcrux.