HP 7 or Slate 7 seems to adhere to the US (North American) wifi frequency spectrum. If you are mixing and matching a variety of devices in your home, your wifi router maybe adhering to rest-of-world wifi spectrum. I solved the problem by bringing wifi router back to center channel (6) and my HP 7 latches on reliably. Previously, the router was on auto and was hanging around channel 13 which seems to be outside of range for HP 7 tablet.