Sound

According to this post

1. Make sure your system is updated

sudo apt-get dist-upgrade

2. Download the latest alsa stable snapshot

sudo apt-get install patch
wget ftp://ftp.kernel.org/pub/linux/kernel/people/tiwai/snapshot/alsa-driver-snapshot.tar.gz
tar xf alsa-driver-snapshot.tar.gz
cd alsa-driver
sudo ./configure --enable-dynamic-minors  --without-oss --with-cards="hda-intel"
sudo make
sudo make install

3. Restart your system
4. Go to system > preferences > sound and make sure your Device (last option) is playback: HDA NVIDIA (PulseAudio Mixer)

/etc/X11/xorg.conf

Section "Module"
   Load    "glx"
   Load    "synaptics"
EndSection

Section "InputDevice"
   Identifier      "Generic Keyboard"
   Driver          "kbd"
   Option          "CoreKeyboard"
   Option          "XkbRules"      "xorg"
   Option          "XkbModel"      "pc105"
   Option          "XkbLayout"     "gb"
   Option          "XkbOptions"    "lv3:rwin_switch,apple:badmap"
EndSection

Section "InputDevice"

   Identifier      "Synaptics Touchpad" Driver  "synaptics"
   Option  "SendCoreEvents"        "true"
   Option  "Device"                "/dev/input/mice"
   Option  "Protocol"              "auto-dev"
   Option  "SHMConfig"             "true"
   Option  "New AccelFactor"       "0.03"
   Option  "LeftEdge"              "0"
   Option  "RightEdge"             "1280"
   Option  "RightEdge"             "1280"
   Option  "TopEdge"               "0"
   Option  "BottomEdge"            "800"
   Option  "MinSpeed"              "0.94"
   Option  "MaxSpeed"              "1"
   Option  "AccelFactor"           "0.0015"
#tapping

   Option  "RTCornerButton"        "2"
   Option  "RBCornerButton"        "3"
   Option  "LTCornerButton"        "2"
   Option  "LBCornerButton"        "3"
   Option  "FingerHigh"            "30"
   Option  "FingerLow"             "20"
   Option  "MaxTapTime"            "150"
   Option  "FastTaps"              "0"
   Option  "TapButton1"            "1"
   Option  "TapButton2"            "2"
   Option  "TapButton3"            "3"
#edge scroll

   Option  "VertEdgeScroll"        "0"
   Option  "HorizEdgeScroll"       "0"
   Option  "VertScrollDelta"       "5"
   Option  "HorizScrollDelta"      "0"
#two finger scroll

   Option  "VertTwoFingerScroll"   "1"
   Option  "HorizTwoFingerScroll"  "1"
EndSection

Section "Device"
   Identifier      "Configured Video Device"
   Driver "nvidia"
EndSection

Section "Monitor"
   Identifier      "Configured Monitor"
EndSection

Section "Screen"
   Identifier      "Default Screen"
   Monitor "Configured Monitor"
EndSection

Section "ServerLayout"
   Identifier "Main Layout"
   Screen "Default Screen"
   InputDevice "Synaptics Touchpad"
   InputDevice "Generic Keyboard"
EndSection