Q:

No sound in Ubuntu 18.04 HP notebook

Please note that I have tried all solutions in the below two links:
"Dummy Output" sound in Ubuntu 14.04
No Sound card detected in Sound Settings, although sound works
pulseaudio -k && sudo alsa force-reload does not solve the problem 
pacmd list-cards shows 0 card(s) available. 
When the sound was working fine on my 18.04 before, I tried to modify  /etc/modprobe.d/alsa-base.conf in order to solve a different issue following this answer. But after my sound stop working I removed the added lines which blacklisted the drivers. Could this have caused my problem?
Please help me out, I cannot work without sound on my PC for long
Update:
Since I have Dual Boot on my PC, I booted into Windows in which also the sound was not working, the Windows troubleshooter couldn't identify the problem so I went in Device Managers and reinstalled the Realtek HD Audio Controller, It didn't solve my problem, the sound still wasn't playing but a remarkable thing that occured was when I booted back into Ubuntu 18.04, it detected a Built-in Audio 
and now pacmd list-cards shows :
1 card(s) available.
index: 0
name: <alsa_card.pci-0000_00_1f.3>
driver: <module-alsa-card.c>
owner module: 7
properties:
    alsa.card = "0"
    alsa.card_name = "HDA Intel PCH"
    alsa.long_card_name = "HDA Intel PCH at 0xa1428000 irq 128"
    alsa.driver_name = "snd_hda_intel"
    device.bus_path = "pci-0000:00:1f.3"
    sysfs.path = "/devices/pci0000:00/0000:00:1f.3/sound/card0"
    device.bus = "pci"
    device.vendor.id = "8086"
    device.vendor.name = "Intel Corporation"
    device.product.id = "9d70"
    device.product.name = "Sunrise Point-LP HD Audio"
    device.form_factor = "internal"
    device.string = "0"
    device.description = "Built-in Audio"
    module-udev-detect.discovered = "1"
    device.icon_name = "audio-card-pci"
profiles:
    input:analog-stereo: Analog Stereo Input (priority 60, available: unknown)
    output:analog-stereo: Analog Stereo Output (priority 6000, available: unknown)
    output:analog-stereo+input:analog-stereo: Analog Stereo Duplex (priority 6060, available: unknown)
    output:hdmi-stereo: Digital Stereo (HDMI) Output (priority 5400, available: no)
    output:hdmi-stereo+input:analog-stereo: Digital Stereo (HDMI) Output + Analog Stereo Input (priority 5460, available: unknown)
    output:hdmi-surround: Digital Surround 5.1 (HDMI) Output (priority 300, available: no)
    output:hdmi-surround+input:analog-stereo: Digital Surround 5.1 (HDMI) Output + Analog Stereo Input (priority 360, available: unknown)
    output:hdmi-surround71: Digital Surround 7.1 (HDMI) Output (priority 300, available: no)
    output:hdmi-surround71+input:analog-stereo: Digital Surround 7.1 (HDMI) Output + Analog Stereo Input (priority 360, available: unknown)
    output:hdmi-stereo-extra1: Digital Stereo (HDMI 2) Output (priority 5200, available: no)
    output:hdmi-stereo-extra1+input:analog-stereo: Digital Stereo (HDMI 2) Output + Analog Stereo Input (priority 5260, available: unknown)
    output:hdmi-surround-extra1: Digital Surround 5.1 (HDMI 2) Output (priority 100, available: no)
    output:hdmi-surround-extra1+input:analog-stereo: Digital Surround 5.1 (HDMI 2) Output + Analog Stereo Input (priority 160, available: unknown)
    output:hdmi-surround71-extra1: Digital Surround 7.1 (HDMI 2) Output (priority 100, available: no)
    output:hdmi-surround71-extra1+input:analog-stereo: Digital Surround 7.1 (HDMI 2) Output + Analog Stereo Input (priority 160, available: unknown)
    output:hdmi-stereo-extra2: Digital Stereo (HDMI 3) Output (priority 5200, available: no)
    output:hdmi-stereo-extra2+input:analog-stereo: Digital Stereo (HDMI 3) Output + Analog Stereo Input (priority 5260, available: unknown)
    output:hdmi-surround-extra2: Digital Surround 5.1 (HDMI 3) Output (priority 100, available: no)
    output:hdmi-surround-extra2+input:analog-stereo: Digital Surround 5.1 (HDMI 3) Output + Analog Stereo Input (priority 160, available: unknown)
    output:hdmi-surround71-extra2: Digital Surround 7.1 (HDMI 3) Output (priority 100, available: no)
    output:hdmi-surround71-extra2+input:analog-stereo: Digital Surround 7.1 (HDMI 3) Output + Analog Stereo Input (priority 160, available: unknown)
    output:hdmi-stereo-extra3: Digital Stereo (HDMI 4) Output (priority 5200, available: no)
    output:hdmi-stereo-extra3+input:analog-stereo: Digital Stereo (HDMI 4) Output + Analog Stereo Input (priority 5260, available: unknown)
    output:hdmi-surround-extra3: Digital Surround 5.1 (HDMI 4) Output (priority 100, available: no)
    output:hdmi-surround-extra3+input:analog-stereo: Digital Surround 5.1 (HDMI 4) Output + Analog Stereo Input (priority 160, available: unknown)
    output:hdmi-surround71-extra3: Digital Surround 7.1 (HDMI 4) Output (priority 100, available: no)
    output:hdmi-surround71-extra3+input:analog-stereo: Digital Surround 7.1 (HDMI 4) Output + Analog Stereo Input (priority 160, available: unknown)
    output:hdmi-stereo-extra4: Digital Stereo (HDMI 5) Output (priority 5200, available: no)
    output:hdmi-stereo-extra4+input:analog-stereo: Digital Stereo (HDMI 5) Output + Analog Stereo Input (priority 5260, available: unknown)
    output:hdmi-surround-extra4: Digital Surround 5.1 (HDMI 5) Output (priority 100, available: no)
    output:hdmi-surround-extra4+input:analog-stereo: Digital Surround 5.1 (HDMI 5) Output + Analog Stereo Input (priority 160, available: unknown)
    output:hdmi-surround71-extra4: Digital Surround 7.1 (HDMI 5) Output (priority 100, available: no)
    output:hdmi-surround71-extra4+input:analog-stereo: Digital Surround 7.1 (HDMI 5) Output + Analog Stereo Input (priority 160, available: unknown)
    off: Off (priority 0, available: unknown)
active profile: <output:analog-stereo+input:analog-stereo>
sinks:
    alsa_output.pci-0000_00_1f.3.analog-stereo/#0: Built-in Audio Analog Stereo
sources:
    alsa_output.pci-0000_00_1f.3.analog-stereo.monitor/#0: Monitor of Built-in Audio Analog Stereo
    alsa_input.pci-0000_00_1f.3.analog-stereo/#1: Built-in Audio Analog Stereo
ports:
    analog-input-internal-mic: Internal Microphone (priority 8900, latency offset 0 usec, available: unknown)
        properties:
            device.icon_name = "audio-input-microphone"
    analog-input-mic: Microphone (priority 8700, latency offset 0 usec, available: no)
        properties:
            device.icon_name = "audio-input-microphone"
    analog-output-speaker: Speakers (priority 10000, latency offset 0 usec, available: unknown)
        properties:
            device.icon_name = "audio-speakers"
    analog-output-headphones: Headphones (priority 9000, latency offset 0 usec, available: no)
        properties:
            device.icon_name = "audio-headphones"
    hdmi-output-0: HDMI / DisplayPort (priority 5900, latency offset 0 usec, available: no)
        properties:
            device.icon_name = "video-display"
    hdmi-output-1: HDMI / DisplayPort 2 (priority 5800, latency offset 0 usec, available: no)
        properties:
            device.icon_name = "video-display"
    hdmi-output-2: HDMI / DisplayPort 3 (priority 5700, latency offset 0 usec, available: no)
        properties:
            device.icon_name = "video-display"
    hdmi-output-3: HDMI / DisplayPort 4 (priority 5600, latency offset 0 usec, available: no)
        properties:
            device.icon_name = "video-display"
    hdmi-output-4: HDMI / DisplayPort 5 (priority 5500, latency offset 0 usec, available: no)
        properties:
            device.icon_name = "video-display"

Despite detecting this 1 card now, I am still not being able to get any sound, please help out

A:

Install music packages of rhythmbox and amarok with:
sudo apt install rhythmbox amarok

or if they are already installed then:
sudo apt install --reinstall rhythmbox amarok

As I know these packages have some more drivers.
Then reboot.
Sorry, because of package amarok. That was earlier days of Ubuntu.
You could then try following :

sudo apt install rhythmbox clementine

or

sudo apt install --reinstall rhythmbox clementine

(improved answer 10th July 2020)

