Panasonic W4

any yellow exclamation points or question marks in here? Anything disabled?

Have you checked all the volume settings? Double-click the volume icon in the taskbar and make sure everything has the volume up and is not muted. Check everything in Sounds and Audio Devices in the Control Panel.

edit:
You might want to check in the Panasonic W4 support area. I cannot do this, but you are a registered owner.
https://www2.panasonic.com/webapp/wcs/stores/servlet/TCCHomePage?langId=-1&storeId=15001&catalogId=13401

For a $2000+ NB, I'd definitely contact Panasonic if you can't easily resolve this. You have a 3 year warranty, but that could potentially be over by now.

And maybe have a look at this
http://forums.majorgeeks.com/showthread.php?t=151886

Open Device Manager, double click the Audio Driver and in the Properties menu click the Driver tab then click Uninstall. Tick the Delete the driver software for this device and click OK, click reboot later.

Download and install CCleaner to tidy up your Registry. Backup the Registry as you go along, rescan again and again saving as you go until there are no errors left.

Cleaner: Windows

When you first open Ccleaner you will have an option to Analyze or Run Cleaner, after checking the left Pane and making your choices. Delete all Temp Files. If you scroll down you will see a greyed out box that has Advanced next to it. Left click on it and keep pressing OK to all of the responses. I normally Untick Windows Log Files and Memory Dumps as they may come in handy.

You don't have to install all of the add ons or shortcuts just the one to the Desktop.

http://www.ccleaner.com/download

Restart the pC after running Ccleaner and reinstall the sound drivers.