nightmare trying to remove /wordpress from url

I’m trying to remove the /wordpress from my website’s url.

At the moment, wordpress is installed in its own separate folder.

I’ve read these instructions:
http://codex.wordpress.org/Giving_WordPress_Its_Own_Directory

I followed ‘Using a pre-existing subdirectory install’.

After following the instructions my webpage and dashboard displayed:
500 – Internal server error.
There is a problem with the resource you are looking for, and it cannot be displayed.

Some additional info:
It seems I do not have a .htaccess file – (I checked hidden files using Filezilla) – so as recommended I moved the web.config file instead.

Also, some weeks ago – as a result of changing my wordpress site url in General Settings and then not being able to access the site or dashboard – I had to add the following code to my web.config file:
define(‘WP_HOME’,’http://www.zorba.com.co/wordpress’);
define(‘WP_SITEURL’,’http://www.zorba.com.co/wordpress’);

I then discovered this post:
http://codex.wordpress.org/Moving_WordPress?#Moving_WordPress_Within_Your_Site

So, I reversed all the changes made by following the first post and followed the new one. Low and behold – my dashboard now displays:

Warning: require_once(D:\Hosting\2928564\html\wordpress/wp-load.php) [function.require-once]: failed to open stream: No such file or directory in D:\Hosting\2928564\html\wordpress\wp-admin\admin.php on line 30

Fatal error: require_once() [function.require]: Failed opening required ‘D:\Hosting\2928564\html\wordpress/wp-load.php’ (include_path=’.;C:\php5\pear’) in D:\Hosting\2928564\html\wordpress\wp-admin\admin.php on line 30

While the website itself is still showing the old html site i’m trying to replace.

This is a nightmare! Help!