Thanks to our web hosting company, this site, and about a dozen others on the shared hosting environment, went offline. The problem looks to have been either a router or hardware firewall that was no longer forwarding requests to the database server (blocking port 1433). FTP was also out of action so we could not even update the sites with a holding page. Only requests on port 80 seemed to work, so we could still view static html pages and images, but not dynamic pages. In the end we had to move all the sites over to one of our dedicated servers and change the IP address in the DNS. For some sites this took quite a long time to do.

The silver lining of this is that the sites that have been moved on ot the dedicated server now have access to using ASP.net 4. That means that I can rebuild this site from the creaking old classic ASP code to the brand shiny new .NET 4 code (using C# as the programming language, which is much better than VB.net in many ways).