All you miss by not installing with sample data is lots of Joomla related external links and annoying articles that you have to delete.
If you really want to know, install Joomla again in some random place, then when you are done, uninstall it.
Trust me, I've done it before.

Edit: Ouch I see what you mean. Re install it through Fantastico with sample data is my advice.
They have Joomla 1.0 and 1.5, make sure you get the one you want!