|this problem occurred because the network did not assign a network address to the computer.|
Ok, for whatever reason, your computer isn't getting assigned an IP from DHCP. My first suspicion is that you have set something up incorrectly on the wireless side. If you plug that computer in to a LAN port on the router does it work properly and get an IP?
If yes, then I suspect my assumption is correct. If it were me, I'd kill that wireless network and redo it slowly and carefully making note of the SSID and password and try again from the laptop.