I just done a few weeks ago for my friend with Dlink as well. Sorry to say but Dlink seems to be a crappy MFG ( you get what you pay for, I guess ). They are configured differently and it's specific to Dlink's own software set up rather than Wifi in general.
So what I taught my friend is to disconnect and connect it again to make sure the connection works since it's easy (just click on D icon at system tray, view available networks, then hit either connect or disconnect). His problem is that the network would connect fine but it won't allow for Net connection. Only disconnecting manually and re-connecting solved the problem. He is using WEP.