[support] urgently need help for Site off-line error

[Qiubo Su (David Su)]

dear drupal support,i installed and configure my drupal site in local ubuntu
pc. it has been working fine, but after i reboot the pc, it shows the below
error message and can never login to the site to browse the pages.
Site off-line

The site is currently not available due to technical problems. Please try
again later. Thank you for your understanding.
------------------------------

If you are the maintainer of this site, please check your database settings
in the settings.php file and ensure that your hosting provider's database
server is running. For more help, see the handbook<http://drupal.org/node/258>,
or contact your hosting provider.

i login to OS and run mysql, but got the "ERROR 2002 (HY000): Can't connect
to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)"
error message.

i try to login though phpmyadmin, but couldn't login there as well.

in the /var/log/apache2/error.log file, there is below output:

[Wed Nov 03 21:23:25 2010] [notice] Apache/2.2.14 (Ubuntu) DAV/2
mod_fcgid/2.3.4 PHP/5.3.2-1ubuntu4.5 with Suhosin-Patch mod_ruby/1.2.6
Ruby/1.8.7(2010-01-10) mod_ssl/2.2.14 OpenSSL/0.9.8k configured -- resuming
normal operations
[Wed Nov 03 21:24:17 2010] [error] [client 192.168.35.103] PHP Fatal error:
Call to undefined function _system_theme_data() in
/var/www/includes/theme.inc on line 481
[Wed Nov 03 21:24:20 2010] [error] [client 192.168.35.103] File does not
exist: /var/www/favicon.ico

in the /var/log/mysql/error.log file, there is below output:

101103 22:35:28 [Note] Plugin 'FEDERATED' is disabled.
101103 22:35:28  InnoDB: Started; log sequence number 0 44233
101103 22:35:28 [ERROR] Fatal error: Can't open and lock privilege tables:
Table 'mysql.user' doesn't exist

it is much appreciated if you can help with this.

thanks,
qiubo su
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.drupal.org/pipermail/support/attachments/20101103/73116d97/attachment.html