PCI/internal sound card not detected

[Dree]

1) Ubuntu 14.04.4 LTS
2) Don't know
3) This a Dell XPS 13 with Ubuntu 14.04 LTS pre-installed on it. The audio worked when it first arrived,
4) After I accepted some automatic updates from Ubuntu, the sound no longer worked across the system. There were also no sound modules recognised. I installed some using "sudo apt-get install linux-restricted-modules-`uname -r` linux-generic" and rebooted but sound still not working.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: alsa-base 1.0.25+dfsg-0ubuntu4
ProcVersionSignature: Ubuntu 3.19.0-65.73~14.04.1-generic 3.19.8-ckt22
Uname: Linux 3.19.0-65-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.21
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CurrentDesktop: Unity
Date: Wed Aug 3 21:28:44 2016
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-trusty-amd64-osp1-20150720-0
InstallationDate: Installed on 2016-07-06 (27 days ago)
InstallationMedia: Ubuntu 14.04 "Trusty" - Build amd64 LIVE Binary 20150720-04:06
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Title: PCI/internal sound card not detected
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/01/2016
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.3.3
dmi.board.name: 07TYC2
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.3.3:bd03/01/2016:svnDellInc.:pnXPS139350:pvr:rvnDellInc.:rn07TYC2:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: XPS 13 9350
dmi.sys.vendor: Dell Inc.