Hello pdenner,
I understand that your sound is not working correctly.
Do a hard reset.
Turn the computer off.
Remove the power cable and the battery.
Hold down the power button for 15 sec while booth power sources are removed.
This should reset the hardware in the computer.
As you turn it back on tap the F10 key. This will load BIOS setup utility.
Press F9 to load defaults.
Press F10 to save and exit.
When the computer boots back up, check to see if everything is working.
You may be having a problem with the port.
Here is a link to a number to call HP and see what options they nay have to repair the system.
Let me know how everything goes.