Can't connect to Wireless internet

Hi!
I'm a bit baffled (easy done)
Unfortunately I don't seem able to connect to the wireless internet provided at my new accomodation. My laptop recognises the system and states it has "excellent" signal however when i then click to connect, before even asking for my key an error message pops up stating that the provider is no longer available or is out of range.
Bizarrely, when I click to connect to next doors internet provider it simply asks for the key (as one would expect).
Please help me- I have no idea why it would work for the lower signal next door and not the full strength one.

Many thanks,

Amy


I'm not too sure about my configuration/operating system. But it is Windows (definately not Vista) and I'm using (or rather trying to use) explorer (though I dont know what version. I can try and find out though if this will help!