Here's my guide to change ur bgm's in watever sounds u like..
1. first open ur BGM folder in ur CorruptRO folder.
Example: D:\Online Games\Gravity\RagnarokOnline\BGM
2. then delete the number u want to change.
Example: you deleted number 1(LOG IN SCREEN BGM)
3. after that paste the song/sounds and rename it w/ the corresponding number.
Example: put the song( Bad Romance ) in the BGM folder and Rename it to( 01 )
4. now noticed that ur LOG IN SCREEN sounds has been changed...
Ra Ra Ra Ra Ra Ra Gah Gah Ulalahh !!
^^