Once you're happy that the disk is okay, return to the mysql> prompt and run the following: check table table_name; where table_name is the name of your corrupted table. This may or may not fix the problem. This is basically the equivalent to running myisamchk, but without the range of options available with the full application.
Once again, you might find that you are still unable to access your table.MYI (that's the file which actually stores the information for the table). Your last resort is to exit mysql and run myisamchk from your shell prompt, passing in the 'recover' option. This can fix just about any MyISAM corruption and is done as follows:
/usr/bin/myisamchk -r /var/lib/mysql/database_name/table_name.MYI
Note that you may need to change those paths to point to your copy of myisamchk and your data directory. use 'find' and 'locate' to determin where they are on your system.
myisamchk -r is the most useful of all tools to the MySQL DBA in disaster recovery situations and has saved my skin on numerous occasions in the past..