If you haven't already done this, I'd try turning off your computer, and your wi-fi router and then turning them back on.
I've found this helps a lot since we've got so many devices now that hook into the wireless wi-fi -- tv, blue-ray player, desktops, laptop, tablets, phone, guests with their tablets and phones. Our TV, especially, seems to get cranky about connecting after a while without a wi-fi reset.