The Forum is organized as a tree. The top community is the HP Support Forum; under the community are several thematic categories (PC, Notebook,...). Inside each category are various boards (think: bulletin boards). Members post questions to a board (hopefully well chosen) as a topic, and other users reply.
For example, go to the top of the tree and walk down
Just to follow up with this, are you still having issues with the forum layout? If you're trying to find an answer to a particular issue for an HP product you can use the search function, which is the box at the top of the page here that says "Enter Search term" You can then click on the box next to it and click on "Community" to search the entire forum. Hope this and the other answers given by the users here have helped, but please reply if not.