Quick fix for tables marked as crashed in MySQL

First off stop the MySQL database server:

/etc/init.d/mysql stop or service mysql stop

Go into the directory where the tables are stored:

cd /var/lib/mysql

Check each database for errors:

myisamchk -cs a*/*.MYI

If errors found then run the fix:

myisamchk -r a*/*.MYI

Once all checked and repaired, restart the service:

/etc/init.d/mysql start or service mysql start