I recently changed from having a hosted web service to run my own server.
This meant changing my domain name settings to point away from the old name server of the Host. I decided to park the domain with the registrant and use their URL redirection service plus sign up for a domain email service so that I didn't have to run a post office from my server.
All went fine, except it was difficult to check out whether the DNS changes had taken effect because as the server was within my firewall. My laptop connected through my cell phone continued looking at the old host despite having cleared the browser caches and I was mystified why this should be. Even uninstalling the browser and re-installing had no effect. Eventually a light bulb came on and I took a look at the hosts file buried in the Win32/drivers/etc dir. There at the bottom was my domain name and the IP number of my old hosts server. For some reason eons ago I had made an entry, probably when my web Hosting changed servers.
Something to look out for if you are ever in the same situation.............