I was repairing this table suddenly server hanged and when I returned back all tables are ok but this one showing \'in use\' and when I try to repair it doesn\'t proceed.
This is a 100% solution. I tried it myself.
myisamchk -r -v -f --sort_buffer_size=128M --key_buffer_size=128M /var/lib/mysql/databasename/tabloname