FTTC installed but server unreachable

[#1]

I had FTTC installed today without any problems other than remote desktop access to my Acer Windows Home Server from my Windows 7 desktop computer  is broken, as is the Windows Home Server Console connection. Access to shared folders on the server is still working from the desktop machine and full access (remote desktop and console) is working from my laptop.
The WHS icon on the task bar which is usually green is grey and hovering over it shows 'Not connected to server'. If I run the setup software from the CD I get as far as 'Downloading software from your home server <servername> 0% complete' before it changes to 'This operation cannot be completed at this time'.
Anyone any thoughts on what might be the problem and how to get the connection back to where it was?
I'm using the Plusnet supplied Netgear router with the basic 'out of the box' setup.

[#2]

Are you using assigned IP addresses or DHCP assigned and has the network changed? Netgears tend to be 192.168.0.*.
Have you tried pinging things?

[#3]

It was on a fixed IP address, .100 or .50, I'm not sure which but have set both while trying for a solution. Ping works.
I seem to remember that a message relating to 'Network 4' popped up when the router was installed. Certainly, the Windows 7 desktop machine's LAN connectivity is impaired.