If you have MP3, you can easily convert it to WAV format using a free online tool like Media.io Try to keep the file size as small as possible, less than 1 MB. Before we dive into the details, you will first want to find the appropriate WAV audio file. I’ll cover all operating systems below to make this as easy as possible depending on your OS. After that, you need to run a third-party program, and even after that, you must shutdown and restart your computer in a certain way to actually hear the sound. In Windows 8, things get worse if you miss your favorite startup sound because it is completely disabled, so you first need to enable it in the registry. On Windows 7, you need to use a third-party program to change the startup sound because if you try to use Control Panel it won’t do anything. However, if you want to have your own startup and shutdown sounds in Windows, it’s possible.

I’ve never been a big fan of Windows startup or shutdown sounds, which is why I was so happy they were removed in Windows 8.

Changing windows 7 startup sound