I’m having problem to use the Wireless network in my range?

I'm using a laptop and its model is "HP Compaq NC 6000". It does not have WiFi support but is has a wireless connectivity.
I get some wireless network signal, from my home and i configure them myself. The operating system of the laptop is Windows XP service pack 2. When I configure the connection, a notification message comes, that I have got connected. But when I try to use the same setting in my browser, the browser can't find any connectivity!!
Can any one tell me, what is the probable cause of this problem and can you suggest any way to get connected to the wireless network ? Moreover, those servers are not password protected, so there is no basic problem that I find.
Is there any problem with my Laptop or the server?? Please someone, tell me what I can do?? Its very important, so help as soon as possible.
