Summarize:

This is a utility created by Windows enthusiasts, as there is no easy way to change the Windows 8, 7, or Vista startup sound normally. You can download the utility from Winaero. Double-click the downloaded ZIP file and drag the StartupSoundChanger.exe file onto your desktop. You will be shown a small menu of options. It must be in WAV format. You can restore the original sound by running the utility and clicking "Restore". You can search for this or find it in the Start menu. Sounds tab. Apply. Note: You won't be able to hear the startup sound in Windows 8 unless you perform a full shutdown (see next section).
Download the "Startup Sound Changer" program. Extract the utility. Run the utility. Click "Replace" and browse your computer for a replacement sound. Open the Control Panel. Select "Sounds" and then click the . Check the "Play Windows Startup sound" box and click .