This, is it the Netgear router or the newer home hub?
if Netgear then this again, mine dropped out all the time but there are 5 of us trying to attach to it via wifi at times.
Have just tried the old unplug it & leave it 10 mins on the router thing?
I am not fully up tp speed with wifi, I dont pretend to be, so if its rubbish I am talking sorry, but my sky/netgear router would do this all the time with multiple users, phones, laptops etc, there was usually one device that was struggling to attach/link up.