Let's see how to change the windows startup sound in Win VISTA/7.
Step1: Goto Control panel
Step2: Click on "Sound"
Step3: Click on "Sounds" tab
Step4: Choose "Windows Logon" from the list
Step5: Now either choose different sounds from sounds listed in the drop down box or click on "Browse" button and select any different sound to play it.
Step6: Logoff and login back to enjoy your new sound.