Windows start up sound is some thing which you may not want to hear every time, specially when you are booting your computer in room and it may disturb others, or in some cases there are people who are annoyed by the sound everytime windows boots up.
For all those who would like to remove the start up sound and make windows silent
1. Once windows is started, press Window Key+R or locate Start Menu >> Run and type mmsys.cpl
and press Enter key or clock ok button.
2. This will open windows sound dialogue window, click Sound tab then locate the checkbox which says Play Windows start up sound
at the bottom of the dialogue window and uncheck the checkbox as shown in the image below.
3. Click apply button, that’s it done. Windows 7 will now boot up silently every time you boot it.