"When I plug it in all the way, there is either muffled, or no sound at all."
That's a hardware failure. But since it's the 8400m chipset PLUS it's from the dv6000 line (which is the line, not your model) you want to do two google searches and call HP to correct this.
Then a search for:
Since HP fixes this by replacing the main board and reloads the OS then you get a short warranty you may get this fixed for free if you play your cards right.
I am on a laptop right now.
I have been using my headphones for a long time now. They are great quality headphones. All of a sudden, my headphone just went haywire. The sound went muffled. I tried to see if actually worked again if I actually "tapped" it a couple times. The sound came back and muffled back again. Tapped it some more then finally it was working. Except, it then came to me that there was no absolute bass whatsoever. Then, the sound was then muffled again and basically now I can't hear anything at all!!!
If I pull it out and leave it 3/4 of the way, it works fine but sometimes one of either the headphones side stop playing music for 2 seconds. When I plug it in all the way, there is either muffled, or no sound at all.
I need great help and if you assist, I thank you.
HP Pavillion dv6000 Series
Windows XP Professional SP2
intel Dual Core 1.8 GHz
2 GB RAM
Realtek HD Audio