Update WordPress for URL change

Hi,

I know the codex goes into some detail regarding this topic but I am having some issues. I am on HostGator btw. I have an install setup and running perfectly fine with a temporary url. I just had my domain transferred over to HostGator and now need to update WordPress to use the new URL. However, no matter what I try, I get a 404 error page.

ex.

current url: (customnumbers).hostgator.com/(port#)/~(publichtmlfolder)

change to: (newdomainname).net

I am not changing the WordPress install folder. Everything is in the same location, its just the domain that I need to change. Any thoughts?

Thanks