Boot up sound change?

Im trying to change the boot up sound...to this wave file.. I did 2 things niether worked..

1 I went into active sync.windows folder and erased the phone on wav file and renamed the one i want to phone on .. now theres no start up sound at all

2 i went into reg edit..hkey local..htc..startup animation... there was no values so i made 1... that didnt work either. idk wat im doin i just tryed that out.. what can i do