They supplied both routers.
Do you have to keep the HomeHub one switched on all the time?
In the days of the 'frog' USB broadband modem, that got turned off when you turned off the PC because it was powered by the USB port. I can't see that there'd be much difference in turning off an ADSL router. I would suggest that when turning it back on to do this before turning on your PC.
Thanks Pani and Eccs I will make sure Creature Obeys.
Well, Creature has checked,and the old router is working now. It has all its lights on except for the Power light.
So it is clear that the fault was Elsewhere but has been put right.
Creature will use the Hub in future as the old router may well be on its last legs. But it still seems to be ok enough to be kept as a spare.
Well that was a good result anyway since you now have both of them. 
Creature has made modifications to his security settings on the Hub.
He has changed one setting in the wireless security bit to No New Stations Allowed, and also changed it from a WEP security to a WAP security thingy.
He has kept the disabled on the wireless anyway, but thought it a good idea to do these other things as well.