Another thought - if you have an iPad or an iPhone (or equivalent), enable wifi on that device, connect to the internet through your home wifi/internet connection, and see if you get access that way. If you do, it means that the problem is on your side of the wifi router or internet connection, and that might help you figure out exactly what the problem is. If you don't, the next test would be to take one of your computers (a small one) and iPad/iPhone to someone else' internet connection (I hear you have lots of Starbucks...). If you can connect through a borrowed internet connection, the problem is probably in your internet connection...
Regards