MySQL Service is not starting on linux I am having a problem with my database it does not want to start :( 

the server is running on linux centos 6.2

it was working until I emptied the logs I don't know if this have anything to do with my problem ! 

the log says the following :

131212 15:52:05 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
131212 15:52:06  InnoDB: Initializing buffer pool, size = 8.0M
131212 15:52:06  InnoDB: Completed initialization of buffer pool
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
131212 15:52:06  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
131212 15:52:06  InnoDB: Started; log sequence number 2 2565027428
131212 15:52:06 [ERROR] Fatal error: Can't open and lock privilege tables: Can't find     file: 'db' (errno: 2)
131212 15:52:06 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended


Edit

here is my "my.cnf" :

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

user=mysql
max_connections=1500
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid


also this is the output of ls -l /var/lib/mysql/ :

-rwxr-xr-x 1 mysql mysql 1512046592 Dec 12 17:02 ibdata1
-rwxr-xr-x 1 mysql mysql    5242880 Dec 12 17:19 ib_logfile0
-rwxr-xr-x 1 mysql mysql    5242880 Dec 11 09:54 ib_logfile1
drwxr-xr-x 2 mysql mysql       4096 Dec 12 09:02 mysql
drwxr-xr-x 2 mysql mysql      12288 Dec 12 17:15 nagios
drwxr-xr-x 2 mysql mysql      20480 Dec  9 09:05 nagiosql
drwxr-xr-x 2 mysql mysql       4096 Oct 27 10:45 test


any suggestions?
I was able to solve this problem by doing the following :


Move all the contents of my data directory (in my case /var/lib/mysql/ ) to a safe place.
Execute the command service mysqld start, this will:

recreate two DBs: 

mysql
test

recreate ibdata1, ib_logfile0, and ib_logfile0

Copy the contents that you backed up (in step 1) from the safe place to the data directory again, of course, except both mysql and test directories.
Using the following command mysqladmin -u root -p'' password yournewpass reset the password of your root user.


An Advice:

Always make sure you make a backup of your databases structure and data to avoid looping in such loops, just delete every thing, re-install your engine, and restore your data :)