Hermione Granger, Ron Weasly, a gnome who used to work at Gringotts, Lord Voldemort. Perhaps I am missing a few more names...
Voldemort and Harry's own intelligence.
help me to find porcupine quills in harry potter
yes
The story of Harry Potter and The Half-Blood Prince is mostly about the horcruxes, Snape, and the book. The half- blood prince is Severus Snape, Harry's professor in Defense Against the Dark arts. Harry finds the first horcrux with the help of Professor Dumbledore, they destroy it to make Voldemort weak. Harry find a book that belong to the half-blood prince (Snape), the book was the source of praise Harry got in his Potions class it was also the source of trouble.
Not directly. Snape shows Harry that he was actually always helping him. He protects Harry, but still kind-of hates him.
he tries to help Harry survive in the Sorcerer's Stone.
He is a vital character to the seventh book and it is very likely he will appear. However it has yet to be confirmed as to whether or not he will be in it. Yes, he is in the movie. He helps Harry Potter find Mundungus with the help of doby.
The boat house. Use the Marauders map to help you.
Harry found all of them with the help of Ron and Hermione.
His bravery, the help of his friends, magic
Griphook the goblin.
Hermione helps Harry and Ron get past the devil's snare on their way to find the sorcerers stone. And she also solves Snape's riddle for Harry so he can get into the room where the sorcerers stone is.