as long as you have a favicon.ico in the web folder it won't use the defaultfavicon.ico.
However it may take a few days before the browser asks for the favicon again, so even though you have the icon in your web folder now you may need to suffer with the old one in the browser for a bit.
you can test to see if the new favicon is working by accessing the site from a browser that hasn't accessed your site before.
cheers
Bruce