Connectivity issue with our D-Link DWL-122 wireless adapter
It could be one of three problems - either the network adapter in your desktop PC has gone bad, the router or ports of the D-Link have gone bad or the cable you are using to connect the two is damaged. The wireless could continue to work if any of the three are problems.
Check that you have link lights on the back of the PC - you should see two where the network cable plugs in and one should flash when sending & receiving data. Also check that the corresponding light on the D-Link for the port you are plugged into is lit. Try different jacks on the D-Link as well.
To tell if the problem is the PC or the D-Link you need to connect another computer to the D-Link. Can you plug in the laptop (disconnect from your wireless first) and physically plug that in - if you have network connections in & out the D-Link is fine and your network card could be the problem. If no connection to the internet is available when plugged in to the D-Link your router is the problem or a setting in the network properties of the PC could be to blame (the latter unlikely if you recently reformatted).
You could continue to use the D-Link for wireless and pick up a 5-Port Switch or something similar to share the network connection - one going to your desktop PC, another line to the D-Link. This is a cheaper solution than getting a new wireless router.
I hope this helps....