Power outage or a buggy mysql version could cause this error to appear:
Stops any php scripts from running etc..
mysql: Table ‘database/table’ is marked as crashed and should be repaired
To fix this, I ran this command via a shell:
$ mysqlcheck --all-databases -uroot -p
enter the root password, and it goes through checking all database tables for issues. hopefully fixing along the way 
You may have to change root to whatever database username you have available (ie: whatever you use to login to phpmyadmin)
It any show the error, run this sql:
$ mysql -uroot -p databasename REPAIR TABLE tablename;
Or just jump into phpmyadmin and click on repair
