Wifi network address problem/ question

[AppleCrumbDlite]

I'm at my parents house now. Brought my laptop to use whenever because I'm here for a week. I know how to set up wifi normally, i've done it quite a few times. But this time I click on the appropriate wifi name, then enter the wep. It accepts it, then gets stuck on acquiring netowrk adress for a minute or so then tells me limited or no connectivity. But I have full signal strength. And when I pit the cursor over it says the signal strength is excellent but could not acquire a network address. Does anyone know what's going on or how I could go about connecting it? I powered the modem and router down and that didn't work.

(I'm on my phone now if you're wondering )