wifi adapter help..connection says acquiring network address

so I just moved into a new place, and the landlord upstairs has internet. she said I could use her wifi for free, and she give me the key number and the password to access it. The wifi works fine on my ipad and my phone, but for some reason when I try (with a wifi adapter) on my desktop pc, it says the connection signal is very good, but it stays on "acquiring network address" and ends up not being connected to the internet. I have tried to "repair" the connection, but it gets stuck on "renewing IP address" and still never ends up successfully connecting to her wifi. any ideas as to what I should do? I really want to get connected here. thank you!