One needs to be very careful before deleting files as once deleted the files are gone for good. A friend of mine today called as MySQL was failing to start on his server. Earlier when "cleaning" his server, he had deleted binary log files without fully understanding their role. When I logged in to his server, I noticed the following errors:
060716 17:21:53 mysqld started
060716 17:21:53 InnoDB: Started; log sequence number 0 1736000119
/usr/sbin/mysqld: File './mysql-bin.000002' not found (Errcode: 2)
060716 17:21:53 [ERROR] Failed to open log (file './mysql-bin.000002', errno 2)
060716 17:21:53 [ERROR] Could not open log file
060716 17:21:53 [ERROR] Can't init tc log
060716 17:21:53 [ERROR] Aborting
060716 17:21:53 InnoDB: Starting shutdown...
060716 17:21:55 InnoDB: Shutdown completed; log sequence number 0 1736000119
060716 17:21:55 [Note] /usr/sbin/mysqld: Shutdown complete
060716 17:21:55 mysqld ended
I deleted the entries from mysql-bin.index and MySQL started without a problem.