Changing the hinges yourself is a little bit risky , because you have to take apart the laptop to get to the screen , then you have to take the screen apart and then take the hinges apart from the screen and this is risky because your screen will have a very delicate cable behind it , and if something happens to that cable your image will be ruined.
Even though it's really expensive to fix it , I suggest letting HP fix its own problem.Especially if it's hinges because it's really hard to find them. I have a HP Pavilion zv5000 with broken hinges and I could find any in Lebanon , so I improvised by drilling holes into the back body and install hinges from another laptop from the outside...
Also I have
discussed this topic before.