Make sure the antenna is away from any metal work and that the orientation is such that you are not 'above' the top of the antenna as there will be a null in the radiation pattern.
The propagation will be affected by location and antenna orientation, try various positions.
BTW, my own netgear just stopped working and I tried all I could, only the intervention of a friend, who rest everything and started trying all permutations until it 'started' again?
Matt