Windows 7 x64
After loading Windows 7 on the E6420 and installing the audio driver from support.dell.com the audio devices show up in device manager as enabled, (IDT High Difinitin Audio CODEC and Intel Display Audio), they show up in the Playback tab of the Sound property in the control panel. Where the issue is in the systray, the audio shows up with the red X and states the "Audio device is disabled". After running the Windows 7 troubleshooter it attempts to enable the devices (though it shows up in Device Manager as enabled) but it states it fails to enable the device. After some more troubleshooting I also get the error, "No speakers or headphones are plugged in"
Troubleshooting steps taken:
See the Windows 7 troubleshooter information below.