Please login to your client area and check the network status. If your server is up and running, then you need to check for any network problems between your computer and the server. To help troubleshoot this, you can take a traceroute.
To do a traceroute on your windows xp computer, please follow this:
Start : Programs : Accessories : Command Prompt
Once there, enter this command:
tracert YOUR_DOMAIN_COM
and
tracert YOUR_IP