Plesk Fatal Exception - MySQL Gone!

[joecostello]

Out of the blue no sites work, mysql has disappeared and i can't login to plesk:

ERROR: PleskFatalException
Unable to connect to database: mysql_connect() [<a href='function.mysql-connect'>function.mysql-connect</a>]: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

0: /usr/local/psa/admin/plib/common_func.php3:190
psaerror(string 'Unable to connect to database: mysql_connect() [<a href='function.mysql-connect'>function.mysql-connect</a>]: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)')
1: /usr/local/psa/admin/auto_prepend/auth.php3:93

Upon starting PSA:
[root@halal mysql]# /etc/rc.d/init.d/psa start
Starting xinetd service... done
Starting named service... done
Starting mysqld service... not installed
Starting qmail service... done
Starting courier-imap service... done
Starting postgresql service... not installed
Starting psa-spamassassin service... done
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
websrvmng: Unable to connect to Plesk Database: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
System error 2: No such file or directory
websrvmng: Unable to connect to Plesk Database: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
System error 2: No such file or directory
websrvmng: Unable to connect to the mysql database

System error 2: No such file or directory
websrvmng: Unable to connect to the mysql database

System error 2: No such file or directory
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
Starting Plesk... done
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)


Upon Starting Mysqld:
[root@halal mysql]# service mysqld start
mysqld: unrecognized service

[root@halal mysql]# /etc/rc.d/init.d/mysqld start
-bash: /etc/rc.d/init.d/mysqld: No such file or directory


I don't know how, but mysql appears to have been removed. I need to reinstall it to get all my sites working again. Can someone tell me the best way to go about this?

I have no idea exactly which version was being used, nor exactly which 8xxx version of plesk im using because i only have access via SSH.

Thanks in advance.