how to change long ip to a sub-domain name

I recently had problems configuring the paypal support because it would not accept the long name of the address using the ip of my server, so a friend of mine fixed that problem real quick by adding a sub-domain instead. My question is that once you click on any link on my main page you automatically have the long ip name in your browser, so how do I keep my sub-domain name showing instead of the long ip? Here's my shop so far, only 1 pic so far for testing and it's not done so please don't try and order anything hehe.
http://zencart.sandysandersdesigns.com/
Just showing so someone in the know will see exactly what I'm talking about once you click on any link. (I'd like to keep the sub-domain name showing so people feel like they are still on "my site" even though it's just a themed out zen cart page ya' know?)

Thanks,
:cheers:

This FAQ talks about the process of moving from one folder to another while on the same server:
https://www.zen-cart.com/tutorials/index.php?article=122

Not to sound dumb, but by doing all this it will keep my sub-domain name showing instead of the long ip name that shows once you click on any link on the main page? The only reason I ask is that in this thread: http://www.zen-cart.com/forum/showthread.php?t=75378
it looks like this guy is asking the same thing I am.

Thanks again for the help!

Nevermind I think I just fixed it by making the necessary changes to made includes/configure.php and admin/includes/configure.php

Thanks for the help and quick reply though!

It looks like you have a lot of redundant path elements in there, though I couldn't tell you how to change most of that safely.

You can for sure eliminate the /zen-cart-v1.3.7-full-fileset-12302006/ part by moving all its contents to /catalog/ or to /public_html/ and editing your configure files accordingly.