I have a similar problem...kinda.
In my home, My laptop has no problem getting wifi conection, BUT when I do, my cousin that has a laptop too, has no acces to internet.
Right now I'm in my uncle's house, where 2 cousins have laptops (an Asus, like myself, and a Dell) and we are having difficulties connecting to internet.
If I'm connected to internet, one of my cousins can't, or if they have, I can't connect.
Is strange when the 3 of us can be connected at the same time.
I dunno what to do, it was not happening when I bought my laptop, and I haven't installed anything strange besides the 15.8 driver.
(My Asus is Windows 8, the other Pcs are Windows 7)