mySQL 5.1 changed innodb_log_file_size getting error on restart In order to optimise my MySQL 5.1 (running on Window 2008 WebServer). I changed a few InnoDB options in my.ini namely the innodb_buffer_pool_size and innodb_log_file_size. But now when I am trying to restart the service it won't start. In the event viewer I can see the following errors:

Unknown/unsupported table type: INNODB 

I have read about deleting log files and then starting the service but I have no clue where those log files are on windows machine. Also what is the best way to recover from this trauma without loosing any table data ?
Yup, you'll need to remove the log files to change their sizes.  They're in where ever your DATADIR is.  Just make sure you remove them when the server is shutdown.  Then restart and you'll be fine (it will recreate them).

DO NOT remove any ibdata files, though.  That has your actual persistent data.