Since Dell rarely sells desktop computers with wireless adapters, it is most likely that someone installed the D-Link wireless adapter after you purchased the computer.  After you re-installed Windows, you need to first install the chipset drivers, and then install the drivers for other devices.  If you can't find a CD with the drivers for the D-Link wireless adapter, you will have to go to the D-Link website, download the drivers on a computer with an internet connection, copy them to removable media, then install them on the computer.  You did not tell us which model computer you have or which model D-Link wireless adapter you have, so it is difficult to provide you with more detailed information.

 

Steve