Messy URL Issue!!!

A friend approached me and asked if I could make a “Custom” WordPress site for him. Having a little bit of knowledge about making websites I naively told his yes… He already had his website domain registered with a service and all of that (www.fatcow.com), so I was working with what they had already done.

The idea was to have a separate landing page to come up when visitors first visited the site and the links to link out to WordPress pages. (www.mustachebox.com) and (www.mustachebox.com/wordpress)

I noticed the option under the “General” tab for “Site Address” and “WordPress Addresses” and thought this could easily be the answer I was looking for. I thought I would be able to have the landing page .html in the main root folder and then have WordPress installed in a subfolder. I followed the instructions provided to the letter. (http://codex.wordpress.org/Giving_WordPress_Its_Own_Directory)

This did not work out for me at all because now I am unable to get to the WordPress pages associated with the domain that my friend registered, which means I can’t just change it back.(http://www.mustachebox.com/wordpress/) I quickly get a 500 Internal Server Error, or when I tried to fix it I came up with a 403 Forbidden.

I have tried deleting the installation from file manager on the hosting site, deleting the MySQL databases from the hosting service, and reinstalling WordPress. Among a number of other things I read might be causing the issue, but have not been able to fix it and am in need of dire help… So if you have any idea how I can fix this or possibly just totally get rid of everything so I can start the WordPress sites over again I am all ears!

Anything help is greatly appreciated!

The blog I need help with is http://www.mustachebox.com.