Hi:
There is only one antenna connected to the wifi card in your notebook.
It could be possible that the wifi antenna is connected to the auxiliary terminal on the wifi card instead of the main terminal.
This has been known to happen from time to time.
That could be causing the issues you are having.
Unfortunately, it is pretty difficult to get to where the wifi card is located.
But checking to see that the antenna is connected to terminal 1 (Main) instead of terminal 2 (Aux), would be the only suggestion I can offer.
Here is the link to the service manual. The wifi card R & R procedures can be found in chapter
http://h10032.www1.hp.com/ctg/Manual/c04642845