Can't connect to wireless networks on a Dell Latitude D430
Do you have an Intel wireless network card?
If yes, have a look in the router configuration whether it uses 802.11n or ~b or ~g. Lately I had a problem with this. Although I got connected to my WLAN I couldn't reach any other PC or the internet. With some help of the guys in my local IRC channel we figured out that Intel cards have problems with 802.11n in Linux. So I forced my router to use b/g instead and then it worked.
This may differ from your problem but who knows which kind of problems occur with this buggy Intel driver.