Since you really have provided no details, such as your vhost info, its pretty hard to say.
If you used the NameVirtualHost directive, you will have to access them by their 'Names', as listed in their ServerName entries.
Did you follow the example in \xammp\apache\conf\extra\httpd-vhosts.conf?
Beyond that - the metaphysical answer to your question is "read and understand".
Good Luck