C521 Wireless Connection is never identified

I have a Dimension C521 which I have always connected to the internet via direct connection from my router via the lan port.  Recently, I've had to move the computer to another location and am trying to connect to the internet via a wireless network card.  While the card connects to the router OK, the wireless connection is never identified so I have local access but no internet connection.  I have tried all of the options suggested by Microsoft to address this issue in Vista but none have worked.  I'm using the latest drivers from DLink, the wireless network card manufacturer.  Is there something about the C521 that prevents it from identifying a wireless connection but not a connection to the lan port?