11.04を使っていたのですが、突然音が出なくなりました。
過去のトピックをみて以下のコマンドを実行してみましたが自分では解決策がわかりませんでした。


$ lspci |grep Audio
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 05)
01:00.1 Audio device: nVidia Corporation High Definition Audio Controller (rev a1)


$ pacmd list-cards;
Welcome to PulseAudio! Use "help" for usage information.
>>> 2 card(s) available.
    index: 0
    name: <alsa_card.pci-0000_01_00.1>
    driver: <module-alsa-card.c>
    owner module: 4
    properties:
        alsa.card = "1"
        alsa.card_name = "HDA NVidia"
        alsa.long_card_name = "HDA NVidia at 0xfbc7c000 irq 16"
        alsa.driver_name = "snd_hda_intel"
        device.bus_path = "pci-0000:01:00.1"
        sysfs.path = "/devices/pci0000:00/0000:00:03.0/0000:01:00.1/sound/card1"
        device.bus = "pci"
        device.vendor.id = "10de"
        device.vendor.name = "nVidia Corporation"
        device.product.id = "0be2"
        device.product.name = "High Definition Audio Controller"
        device.string = "1"
        device.description = "High Definition Audio Controller"
        module-udev-detect.discovered = "1"
        device.icon_name = "audio-card-pci"
    profiles:
        output:hdmi-stereo: Digital Stereo (HDMI) Output (priority 5400)
        output:hdmi-surround: Digital Surround 5.1 (HDMI) Output (priority 300)
        output:hdmi-stereo-extra1: Digital Stereo (HDMI) nr 2 Output (priority 5200)
        output:hdmi-stereo-extra2: Digital Stereo (HDMI) nr 3 Output (priority 5200)
        output:hdmi-surround-extra2: Digital Surround 5.1 (HDMI) nr 3 Output (priority 100)
        output:hdmi-stereo-extra3: Digital Stereo (HDMI) nr 4 Output (priority 5200)
        output:hdmi-surround-extra3: Digital Surround 5.1 (HDMI) nr 4 Output (priority 100)
        off: オフ (priority 0)
    active profile: <output:hdmi-stereo>
    sinks:
        alsa_output.pci-0000_01_00.1.hdmi-stereo/#0: High Definition Audio Controller Digital Stereo (HDMI)
    sources:
        alsa_output.pci-0000_01_00.1.hdmi-stereo.monitor/#0: Monitor of High Definition Audio Controller Digital Stereo (HDMI)
    index: 1
    name: <alsa_card.pci-0000_00_1b.0>
    driver: <module-alsa-card.c>
    owner module: 5
    properties:
        alsa.card = "0"
        alsa.card_name = "HDA Intel"
        alsa.long_card_name = "HDA Intel at 0xf9ff8000 irq 47"
        alsa.driver_name = "snd_hda_intel"
        device.bus_path = "pci-0000:00:1b.0"
        sysfs.path = "/devices/pci0000:00/0000:00:1b.0/sound/card0"
        device.bus = "pci"
        device.vendor.id = "8086"
        device.vendor.name = "Intel Corporation"
        device.product.id = "3b56"
        device.product.name = "5 Series/3400 Series Chipset High Definition Audio"
        device.form_factor = "internal"
        device.string = "0"
        device.description = "内部オーディオ"
        module-udev-detect.discovered = "1"
        device.icon_name = "audio-card-pci"
    profiles:
        output:analog-stereo: Analog Stereo Output (priority 6000)
        output:analog-stereo+input:analog-stereo: Analog Stereo Duplex (priority 6060)
        output:analog-surround-40: Analog Surround 4.0 Output (priority 700)
        output:analog-surround-40+input:analog-stereo: Analog Surround 4.0 Output + Analog Stereo Input (priority 760)
        output:analog-surround-41: Analog Surround 4.1 Output (priority 800)
        output:analog-surround-41+input:analog-stereo: Analog Surround 4.1 Output + Analog Stereo Input (priority 860)
        output:analog-surround-50: Analog Surround 5.0 Output (priority 700)
        output:analog-surround-50+input:analog-stereo: Analog Surround 5.0 Output + Analog Stereo Input (priority 760)
        output:analog-surround-51: Analog Surround 5.1 Output (priority 800)
        output:analog-surround-51+input:analog-stereo: Analog Surround 5.1 Output + Analog Stereo Input (priority 860)
        output:analog-surround-71: Analog Surround 7.1 Output (priority 700)
        output:analog-surround-71+input:analog-stereo: Analog Surround 7.1 Output + Analog Stereo Input (priority 760)
        output:iec958-stereo: Digital Stereo Duplex (IEC958) (priority 5500)
        output:iec958-stereo+input:analog-stereo: Digital Stereo (IEC958) Output + Analog Stereo Input (priority 5560)
        input:analog-stereo: Analog Stereo Input (priority 60)
        off: オフ (priority 0)
    active profile: <output:analog-stereo+input:analog-stereo>
    sinks:
        alsa_output.pci-0000_00_1b.0.analog-stereo/#18: 内部オーディオ Analog Stereo
    sources:
        alsa_input.pci-0000_00_1b.0.analog-stereo/#24: 内部オーディオ Analog Stereo
        alsa_output.pci-0000_00_1b.0.analog-stereo.monitor/#25: Monitor of 内部オーディオ Analog Stereo


おそらく

　off: オフ (priority 0)

の部分が原因なのではないかと思うのですが、直し方がわかりません。
サウンド設定のプロファイルはAnalog Stereo Duplexを選択しています。
どなたか詳しい方がいましたら、宜しくお願いします。