I'm sorry to say that the real problem is, HP are selling laptops with a fault that causes this buzzing sound. They know about it, but are doing nothing other than giving people a run around of useless 'fixes'.
I'm using a faulty HP right now. This is the last HP product I will ever buy. Not because of the fault, but because of HP's attitude and couldn't care less approach to paying customers.
Whilst I will never buy HP again, I will devote some of my time from this point on, posting about HP's poor quality and service on every social networking and bulletin board site I can find.