Connected to WPA-secured network, but no internet [closed]

My Ubuntu machine can connect to my WPA network, but there's not a trickle of internet to be found. It works fine with another (but farther) WEP network.

Windows system on the WPA network work fine (I'm using one to write this question). Wired connection to the router broadcasting the problematic network is also fine.

Do note that I did not try to connect to network using Windows on the same machine. It's an Atheros card - I will include more details if requested.

Oh and I the other systems on the network are visible as well.

EDIT I've removed the Ethernet details from the following output:

~$ sudo lshw -class Network

  *-network
       description: Wireless interface
       product: AR5001 Wireless Network Adapter
       vendor: Atheros Communications Inc.
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlan2
       version: 01
       serial: 00:22:69:18:f1:d3
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=ath5k driverversion=2.6.38-8-generic firmware=N/A ip=192.168.2.7 latency=0 link=yes multicast=yes wireless=IEEE 802.11bg
       resources: irq:18 memory:55200000-5520ffff

Good network connection without Internet access could mean that you are behind a proxy server. Check in the working computers if a proxy is set and you can add it in Ubuntu with in System -> Preferences -> "Network Proxy".

To validate if this is your problem, you should be able to ping a website in the terminal using for instance > ping www.google.com but the browser will not be able to access to the website.

If the ping fails, then the proxy is probably not your problem. You could then check if you have a DNS server in /etc/resolv.conf and set one if not. I usually test with OpenDNS (208.67.222.222 or 208.67.220.220) when something is not working because it is available most of the time and from anywhere. Set these two addresses in /etc/resolv.conf like this:

nameserver 208.67.222.222
nameserver 208.67.220.220

and then try to ping a website again. If ping works but there is still no internet in the browser, then check proxy as described above and add it if necessary.

Hopefully the Internet connection will work after trying this...