If you have properly updated your DNS information to use Winhost's name servers yet the domain does not work or is still pointing to the previous hosting company, you are likely experiencing DNS Caching.
After you make the update with your domain registrar, the Internet will not instantly recognize your new domain name information. All modifications and new registrations need to be synchronized with the central (root) DNS servers. This process typically takes an hour or two, but can take as long as 72 hours. Therefore, if you run a whois lookup on your domain name, it may be properly updated in the whois database offered by your domain registrar, however the root DNS servers may not have been updated yet.
Additionally, all Internet service providers maintain their own local DNS cache. So even if the root DNS servers have been updated with your domain's new name servers, the ISPs local DNS servers can still cache your old information. In which case users of that ISP will still be taken to your previous location, while users of other ISPs will be taken to your new location.
The DNS caching period is a normal and unavoidable.
Mail servers will also send email to different locations depending on the local DNS cache they are using. So it is possible that you may not get all of your email during this DNS caching period. We recommend that you immediately set up all your email addresses, duplicating the email setup at your previous host.
While your DNS changes are propagating, you can use the Secondary FTP address to upload your files and your alternative URL to view your site. Secondary FTP and URL addresses can be found in Control Panel, under Site Info.
Keywords: nameserver nameservers