$ sudo apt-get remove --purge mysql-server-5.0 && sudo rm -rf /etc/mysql/ && sudo apt-get install --reinstall mysql-server-5.0
[sudo] password for johnny:
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package mysql-server-5.0 is not installed, so not removed
The following packages were automatically installed and are no longer required:
  lirc pwgen libfreebob0 libnet-daemon-perl libfaad2-0 liblzo1 libxml-sax-perl
  libparse-yapp-perl libfame-0.9 libxml-perl fftw2 libquicktime1 php5
  libswscale1d libjack0 python-imaging libdbi-perl libpvm3 libmp4v2-0
  libtunepimp5 mplayer libdate-manip-perl libapr1 libxml-namespacesupport-perl
  libapache2-mod-php5 libxml-libxml-perl libmpich1.0c2 apache2-mpm-prefork
  libxml-libxml-common-perl apache2-utils dvdauthor apache2 ruby1.8 libx264-54
  apache2.2-common python-qt3 ruby mplayer-skins libxml-simple-perl libggi2
  python-sip4 expect libgii1 liba52-0.7.4 ffmpeg transcode libxml-regexp-perl
  ntp libifp4 libgii1-target-x libdvdread3 libdc1394-13 tcl8.4 libcdaudio1
  libavformat1d libplrpc-perl libxvidcore4 mjpegtools libpq5 libxml-xql-perl
  libmjpegtools0c2a libruby1.8 libg2c0 libaprutil1 vnc4-common libxml-dom-perl
  liblame0 php5-common libnjb5 libofa0 libmpeg2-4 libfaac0 gcc-3.4-base
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  lirc pwgen libfreebob0 libfaad2-0 liblzo1 libxml-sax-perl libparse-yapp-perl
  libfame-0.9 libxml-perl fftw2 libquicktime1 php5 libswscale1d libjack0
  python-imaging libpvm3 libmp4v2-0 libtunepimp5 mplayer libdate-manip-perl
  libapr1 libxml-namespacesupport-perl libapache2-mod-php5 libxml-libxml-perl
  libmpich1.0c2 apache2-mpm-prefork libxml-libxml-common-perl apache2-utils
  dvdauthor apache2 ruby1.8 libx264-54 apache2.2-common python-qt3 ruby
  mplayer-skins libxml-simple-perl libggi2 python-sip4 expect libgii1
  liba52-0.7.4 ffmpeg transcode libxml-regexp-perl ntp libifp4
  libgii1-target-x libdvdread3 libdc1394-13 tcl8.4 libcdaudio1 libavformat1d
  libxvidcore4 mjpegtools libpq5 libxml-xql-perl libmjpegtools0c2a libruby1.8
  libg2c0 libaprutil1 vnc4-common libxml-dom-perl liblame0 php5-common libnjb5
  libofa0 libmpeg2-4 libfaac0 gcc-3.4-base
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libdbd-mysql-perl libmysqlclient15off mysql-client-5.0 mysql-common
Suggested packages:
  mysql-doc-5.0 tinyca
Recommended packages:
  mailx
The following NEW packages will be installed
  libdbd-mysql-perl libmysqlclient15off mysql-client-5.0 mysql-common
  mysql-server-5.0
0 upgraded, 5 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B/37.7MB of archives.
After unpacking 113MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Preconfiguring packages ...
Selecting previously deselected package mysql-common.
(Reading database ... 106840 files and directories currently installed.)
Unpacking mysql-common (from .../mysql-common_5.0.45-1ubuntu3_all.deb) ...
Selecting previously deselected package libmysqlclient15off.
Unpacking libmysqlclient15off (from .../libmysqlclient15off_5.0.45-1ubuntu3_amd64.deb) ...
Selecting previously deselected package libdbd-mysql-perl.
Unpacking libdbd-mysql-perl (from .../libdbd-mysql-perl_4.004-2_amd64.deb) ...
Selecting previously deselected package mysql-client-5.0.
Unpacking mysql-client-5.0 (from .../mysql-client-5.0_5.0.45-1ubuntu3_amd64.deb) ...
Setting up mysql-common (5.0.45-1ubuntu3) ...
Selecting previously deselected package mysql-server-5.0.
(Reading database ... 106922 files and directories currently installed.)
Unpacking mysql-server-5.0 (from .../mysql-server-5.0_5.0.45-1ubuntu3_amd64.deb) ...
Setting up libmysqlclient15off (5.0.45-1ubuntu3) ...

Setting up libdbd-mysql-perl (4.004-2) ...
Setting up mysql-client-5.0 (5.0.45-1ubuntu3) ...

Setting up mysql-server-5.0 (5.0.45-1ubuntu3) ...
 * Stopping MySQL database server mysqld                                 [ OK ] 
 * Starting MySQL database server mysqld                                 [ OK ] 
/etc/init.d/mysql: line 122: /etc/mysql/debian-start: No such file or directory
invoke-rc.d: initscript mysql, action "start" failed.