I found this guidehttp://neosmart.net/blog/2007/how-to-changing-the-windows-vista-startup-sound/
Go to Control Panel, Account Settings, Account Family and Safety, User Accounts, and Turn UAC on or off.
Set it to off.
You need to take ownership of the file then.
Right click the file, properties, and go to the security tab. Go to advanced, owner, and edit. It says ownership SYSTEM right?
Change that to Administrator. Apply and get out of their. Then go back to the security tab and click on edit and allow the write permission, etc. Whatever you need.
You're welcome.
