Hi Lex200
From above comments from Izzy you will note that you need to do two things.
1. Setup your zone file for both domain and sub domain. I would suggest you take Izzy's advice and open a free account at zoneedit. I did and it was easy to setup.
2. Add the following to your "httpd-vhosts.conf" file. The path to this file is xampp\apache\conf\extra
Below I'm using an example domain name and sub domain for security reasons. I would suggest that you edit your post above and take out your domain name and leave an example too, again for security reasons. Everything I put in brackets is only my comments, don't include them in your vhost config file. I appologies if I make this very simply as I'd rather do this in case you are a newbie like me.
(My program is installed in D drive, you need to change it to C if you have it installed there)
NameVirtualHost *:80
<VirtualHost *:80>
ServerName localhost:80
DocumentRoot "D:/xampp/htdocs"
</VirtualHost>
(business is the example domain name)
(the web sites are in a folder called sites)
<VirtualHost *:80>
ServerName business.co.nz
ServerAlias
www.business.co.nz
DocumentRoot "D:/sites/business.co.nz/" <Directory "D:/sites/business.co.nz/">
Options Indexes FollowSymLinks Includes ExecCGI
AllowOverride All
Order allow,deny
Allow from all
</Directory>
</VirtualHost>
(my.business is the example subdomain name)
<VirtualHost *:80>
ServerName my.business.co.nz
ServerAlias
www.my.business.co.nz
DocumentRoot "D:/sites/my.business.co.nz/"
<Directory "D:/sites/my.business.co.nz/">
Options Indexes FollowSymLinks Includes ExecCGI
AllowOverride All
Order allow,deny
Allow from all
</Directory>
</VirtualHost>
Hope this helps. If you have problems paste here but change the domains to examples before posting.