Solve no sound problem in Ubuntu

One after another 17 days have passed.. till today my laptop was completely silent when i booted into Ubuntu. But now, just 10 mins back, after a lot of hit and trial with driver model, I could make make my laptop speak. Here's what I did.
Though I specified this as ubuntu problem in title, it the problem of alsa; it's not recognizing your device.

I completely forgot what I did to mess up my laptop-sound-system, so i thought to start afresh.
I removed the alsa and pulseaudio completely. And One thing I would like to mention: I am completely unfamiliar about the interaction of alsa and pulseaudio with the sound system. This is my first deal with sound system of linux to this depth.

sudo apt-get --purge remove linux-sound-base alsa-base alsa-utils \
       "pulseaudio-*"

Then I did a quick Reboot; just playing safe. (Jaunty boots on/off so fast, I am fan of it.)
Next I reinstalled the alsa with pulseaudio.

sudo apt-get install linux-sound-base alsa-base alsa-utils \
       libasound2-plugins "pulseaudio-*" paman padevchooser \
       paprefs pavucontrol pavumeter 

Then, I appended following lines to the file /etc/modprobe.d/alsa-base.conf

alias snd-card-0 snd-hda-intel
alias sound-slot-0 snd-hda-intel
options snd-hda-intel model=dell-m6
options snd-hda-intel enable_msi=1

The bold faced "model=dell-m6" was the main hack for the system to work.

Then after another quick boot, I got the sound.

During this I refered a lot of pages, But the most useful and the one that is well documented is: Comprehensive Sound Problem Solutions Guide
And this is the page where I got the model of the sound-card(dell-m6) from.