After a software update, ubuntu thinks there is no sound card

After a routine software update (which updated the kernel) alsa recognises no sound card although lspci reports an audio device: intel corp device 2284 (rev 35). Windows are also sluggish opening - I wonder if this is related?

Here is alsa diagnostic stuff:

upload=true&script=true&cardinfo=
!!################################
!!ALSA Information Script v 0.4.64
!!################################

!!Script ran on: Wed Mar 14 16:50:57 UTC 2018

!!Linux Distribution
!!------------------

Ubuntu 14.04.5 LTS \n \l DISTRIB_ID=Ubuntu DISTRIB_DESCRIPTION="Ubuntu 14.04.5 LTS" NAME="Ubuntu" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu 14.04.5 LTS" HOME_URL="http://www.ubuntu.com/" SUPPORT_URL="http://help.ubuntu.com/" BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"

!!DMI Information
!!---------------

Manufacturer: Dell Inc.
Product Name: Inspiron 15-3552
Product Version: 4.0.9
Firmware Version: 4.0.9
Board Vendor: Dell Inc.
Board Name: 0HTJCH

!!ACPI Device Status Information
!!---------------

!!Kernel Information
!!------------------

Kernel release: 3.13.0-143-generic
Operating System: GNU/Linux
Architecture: x86_64
Processor: x86_64
SMP Enabled: Yes

!!ALSA Version
!!------------

Driver version: k3.13.0-143-generic
Library version: 1.0.27.2
Utilities version: 1.0.27.2

!!Loaded ALSA modules
!!-------------------

!!Sound Servers on this system
!!----------------------------

Pulseaudio:
      Installed - Yes (/usr/bin/pulseaudio)
      Running - Yes

!!Soundcards recognised by ALSA
!!-----------------------------

--- no soundcards ---

!!PCI Soundcards installed in the system
!!--------------------------------------

00:1b.0 Audio device: Intel Corporation Device 2284 (rev 35)

!!Advanced information - PCI Vendor/Device/Subsystem ID's
!!-------------------------------------------------------

00:1b.0 0403: 8086:2284 (rev 35)
 Subsystem: 1028:06ac

!!Modprobe options (Sound related)
!!--------------------------------

snd_atiixp_modem: index=-2
snd_intel8x0m: index=-2
snd_via82xx_modem: index=-2
snd_usb_audio: index=-2
snd_usb_caiaq: index=-2
snd_usb_ua101: index=-2
snd_usb_us122l: index=-2
snd_usb_usx2y: index=-2
snd_cmipci: mpu_port=0x330 fm_port=0x388
snd_pcsp: index=-2
snd_usb_audio: index=-2
snd_hda_intel: jackpoll_ms=500

!!Loaded sound module options
!!---------------------------

!!ALSA Device nodes
!!-----------------

crw-rw----+ 1 root audio 116, 1 Mar 14 16:46 /dev/snd/seq
crw-rw----+ 1 root audio 116, 33 Mar 14 16:46 /dev/snd/timer

!!Aplay/Arecord output
!!--------------------

APLAY

aplay: device_list:268: no soundcards found...

ARECORD

arecord: device_list:268: no soundcards found...

!!Amixer output
!!-------------

!!Alsactl output
!!--------------

--startcollapse--
--endcollapse--

!!All Loaded Modules
!!------------------

Module
nvram
ctr
ccm
input_polldev
ath3k
rts5139
btusb
bnep
rfcomm
uvcvideo
videobuf2_vmalloc
bluetooth
videobuf2_memops
videobuf2_core
videodev
binfmt_misc
snd_hwdep
snd_pcm
snd_page_alloc
snd_seq_midi
dell_wmi
sparse_keymap
snd_seq_midi_event
arc4
nls_iso8859_1
snd_rawmidi
ath9k
coretemp
snd_seq
kvm_intel
kvm
crct10dif_pclmul
snd_seq_device
dell_laptop
crc32_pclmul
dcdbas
ghash_clmulni_intel
snd_timer
ath9k_common
aesni_intel
ath9k_hw
aes_x86_64
lrw
gf128mul
ath
glue_helper
ablk_helper
cryptd
snd
mac80211
joydev
serio_raw
cfg80211
shpchp
soundcore
parport_pc
ppdev
i2c_hid
i2c_algo_bit
mac_hid
lp
parport
btrfs
xor
raid6_pq
libcrc32c
hid_generic
usbhid
hid
psmouse
ahci
libahci
wmi
sdhci_acpi
sdhci

!!ALSA/HDA dmesg
!!--------------

[ 15.699353] input: Dell WMI hotkeys as /devices/virtual/input/input9
[ 15.915553] snd_hda_core: version magic '3.13.0-143-generic SMP mod_unload modversions ' should be '3.13.0-143-generic SMP mod_unload modversions retpoline '
[ 15.915795] snd_hda_core: version magic '3.13.0-143-generic SMP mod_unload modversions ' should be '3.13.0-143-generic SMP mod_unload modversions retpoline '
[ 16.046714] cfg80211: World regulatory domain updated:
--
[ 22.456499] WARNING: CPU: 1 PID: 1065 at /build/linux-0nSM2x/linux-3.13.0/drivers/usb/host/xhci-ring.c:1590 handle_cmd_completion+0xe56/0xe60()
[ 22.456501] Modules linked in: nvram ctr ccm input_polldev ath3k rts5139(C) btusb bnep rfcomm uvcvideo videobuf2_vmalloc bluetooth videobuf2_memops videobuf2_core videodev binfmt_misc snd_hwdep snd_pcm snd_page_alloc snd_seq_midi dell_wmi sparse_keymap snd_seq_midi_event arc4 nls_iso8859_1 snd_rawmidi ath9k coretemp snd_seq kvm_intel kvm crct10dif_pclmul snd_seq_device dell_laptop crc32_pclmul dcdbas ghash_clmulni_intel snd_timer ath9k_common aesni_intel ath9k_hw aes_x86_64 lrw gf128mul ath glue_helper ablk_helper cryptd snd mac80211 joydev serio_raw cfg80211 shpchp soundcore parport_pc ppdev i2c_hid i2c_algo_bit mac_hid lp parport btrfs xor raid6_pq libcrc32c hid_generic usbhid hid psmouse ahci libahci wmi sdhci_acpi sdhci
[ 22.456576] CPU: 1 PID: 1065 Comm: gdbus Tainted: G C 3.13.0-143-generic #192-Ubuntu

The output at step 4 of the official Ubuntu documentation sound trouble-shooting procedure from `lshw -C sound' is

  *-multimedia UNCLAIMED
       description: Audio device
       product: Intel Corporation
       vendor: Intel Corporation
       physical id: 1b
       bus info: pci@0000:00:1b.0
       version: 35
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi bus_master cap_list
       configuration: latency=0
       resources: memory:91310000-91313fff

I want to generate analogue sound output for internal speakers and headphones socket.

STEP 7 says run alsamixer in a terminal. My terminal does not recognise the command.