hmmm... key difference is that with the Voyager installed your PC is expecting to "Dial Up" to its internet connection (even though ADSL is always on). When you uninstalled the software it probably meant your PC had no dial up adapter left and when that happens Windows looks by default to the network for internet connectivity. And using a router effectively means your PC is using the network for its internet connectivity and hey presto it works.

However I find it strange that the lights didn't work on the router. Oh well, its all sorted now and that's the main thing.