To remove End Key Annoying sound, delete the "P" from HKCUControl PanelSoundsEndingScript

http://forum.xda-developers.com/showthread.php?p=2434564#post2434564

[HKEY_CURRENT_USERControlPanelSoundsEnding]
"Sound"="Midi2Wave_079_4098.wav"
"Category"="InCallFeedback"
"Script"="p"

http://forum.xda-developers.com/showthread.php?t=246594