I had noticed today the following errors appearing in my blog
WordPress database error: [Can’t open file: ‘wp_comments.MYI’ (errno: 144)] SELECT COUNT(*) FROM wp_comments WHERE comment_approved = ‘0’
WordPress database error: [Can’t open file: ‘wp_comments.MYI’ (errno: 144)] SELECT COUNT(comment_ID) FROM wp_comments WHERE comment_approved = ‘spam’
This clearly shows that there is a problem with wp_comments table. To fix you can execute the following MySQL query
repair table wp_comments;
and if this did not fix the error or if you do not know the username and password for the wordpress MYSQL database then you can use the Database tab in your wordpress admin section which has an option to Empty/Drop table. Using this you can empty your wp_comments table and this should fix the error. The downside of emptying the table is that your going to lose all the comments that have been posted till now but it is better that living with a corrupt table !!!.