What are the LED status indicators showing on the router? (Your connection might be down).
Does the router work using a wired connection (has the router got a switch to turn off wifi, if it has check its switched on).
I take it you checked all the details in the router settings listed on Tiscalis website and not just the VPI/VCI values?
http://www.tiscali.co.uk/help/broadb..._settings.html
If you haven't got a copy of the manual you can get it from here:
http://62.253.242.27/faqs/downloads/...DSL-C4W-EG.zip