The database is stored in /xampp/mysql/data

Inside the /data folder you will find a number of directories. Each directory corresponds to a database you have created. The files for each database are found inside those directories.

However, directly manipulating those files usually ends badly.

You’re welcome and thanks for the positive feedback

Your browser cannot directly access the MySQL database (or the data inside). To access and display the data, you need to use a script (it could be written in PHP) that accesses the MySQL database and then displays the result in a webpage.
W3Schools has really good tutorials on various web based subjects (so there is no point in me repeating / duplicating them). For example, this page shows how to connect to a MySQL databse using PHP.

Unfortunately, your questions are beyond the scope of the article. The article was about creating a database that can be used by a CMS (like Joomla! or WordPress). It is not about database programming or development.
However …
Microsoft Access is a different database management application. By default Microsoft Access uses the Microsoft Jet Database. The database with XAMPP is MySQL.
You can definitely connect Microsoft Access to MySQL. There is nice tutorial on that here and here (section 21.1.5.4.3 – about half way down the page).
Dream Weaver can definitely be used for web development. Personally, I don’t use it. I use available CMSes (like WordPress and Joomla) and find templates I like (maybe customizing them slightly).
My primary focus is on content creation (writing articles) and not web site development. Sorry.
Thanks again for your question.

XAMPP 1.7.7 is no more complicated to use than XAMPP 1.7.3.
There are two main differences: (1) the look and feel of the GUI has changed a little bit – but the functions are still the same; (2) XAMPP 1.7.7 has stricter error reporting enabled by default – this causes problems with some applications (like Joomla! 1.5, 1.6 and 1.7 – it works fin with Joomla! 2.5).

My best guess is that Vista is blocking the MySQL.
Since I don’t have Vista, I am not sure exactly what it could be, but it might be one of the following:
(1) the Vista firewall has blocked the port (3306) needed to connect to MySQL
(2) Vista is blocking the MySQL service (or application)
(3) perhaps the MySQL app needs to run with administrator privileges.
As I said, I don’t have Vista, so my guesses might be wrong.