Somethings you need to check here.
You need to change the
ns1.nameserver.tld and
ns2.nameserver.tld (ns3, ns4 etc if supplied by your DNS service) at your domain name registrar - like GoDaddy or Enom etc. to point to your name servers. This is not your domain name but your nameservers from your DNS Service Zone File.
You will need to set up a DNS Service with a provider or have Bind installed on your XAMPP server PC.
There are many free DNS services out there, a couple of which I include here. These I have found to be reliable and have used them myself:
Zone Edit
FreeDNS
Zone Edit has domain e-mail forwarding also and for free. FreeDNS does not have that service. Both allow you to set your MX preferences in the zone file.
You would need to open an account, configure that account and change the nameservers that are given you by the DNS Service at your domain name registrar. Only takes a few minutes to achieve all this.
The above services are free for the first 5 domains. Also, for those interested, they have a Dynamic IP facility that works like a charm and sub domains for those who don't have their own domain name.
After setting up your Domain Name Services they can be checked at:
http://dnsreport.com
To make sure all your details are being served to the Internet and are error free.
Hope this helps.