Setting system volume levels
You can set the volume level for system sounds, such as the tone that plays when you synchronize.
1.Go to Applications 
and select Sounds 
.
2.Select the Application pick list and select General.
3.Select the System Volume and Game Volume pick lists and select a volume level.
4.Select Done.
If the Ringer switch is set to no sound, the ringer setting overrides the sound settings and all sounds are turned off.
Your smartphone includes a silent alarm that can vibrate even when the Ringer switch is set to Sound Off.
