There are two things you may wish to review.  First is the order of installation of your drivers following the reinstallation of the OS.  Dells insist on having the Notebook System Software and the Intel Chipset drivers loaded first and in that order.  The remainder is a bit more forgiving, but Dell recommends installing the drivers for video, network (the Broadcom device), and sound in that order following the first two because of the resources they require.  The wireless card should follow those. The second thing is that Dell laptops usually have a control in system setup that turns the wireless port on or off.  You might wish to use F2 during the self test to examine the system setup pages to see whether the card is still listed as being present or has been switched off. This advice is based on your statement that Windows has nothing, to include an unknown device, listed in the device manager that might correspond to your wireless card.  For the card to be completely undetected you would need to be missing the chipset driver, the card would need to be turned off in BIOS, the card may not be physically connected to the computer (you need to re-seat the card to correct this), or the card has failed.
i have a latitude d620 i did a fresh install i have loaded all the drivers in the order specified. when i tried to load the wireless network driver i get an Adapter Error under Device Manager> Network Adapters>     it only shows the Broadcom ethernet adapater; NO wireless adapter How do i install the wireless adapter???? thanks HB
wireless adapter missing