I am with Virgin and was having the same problem for a couple of months, the internet signal would just keep dropping off when using the laptop or ipad. I finally phoned them up, and the man on the phone logged himself into my laptop and i could see him doing stuff on my screen and checking the router. He then told me there was something wrong with the router, which i could see might be the problem as we had a new one a couple of month previously. Anyway, he booked the engineer to come along that weekend. Engineer came, did some test and told me it was nothing to do with the router, but it was the strength of the signal coming into the modem that was far to high, so he said he had turned it right down and tested it again... he did change the router also though, to one of those new super hub things... all has been fine since..... so maybe you could ask them to test the signal strength that you are receiving?? i don't understand all that stuff myself... he told me that the strength was 11, and it only needed to be between 2 and 3?? what ever that means, but as i said, all has been fine since.