Go to the following site, enter your Service Tag number then click on the Original Configuration tab. This will give you a list of components which shipped with the computer, from which you should be able to figure out which wireless network adapter is physically present in the computer.
Did you install the chipset drivers and notebook system software before you installed any other device drivers?
Perhaps if you actually told us which wireless adapter you have in your machine and which driver you installed (rather than just calling it the "correct driver"), we could provide better help. Otherwise you have to rely on my ESP ability, which has never really worked all that well.
I've been thinking about taking the card out and putting it back in, thinking maybe something magical will happen. http://support.dell.com/support/edocs/systems/ins6400/en/sm/cards.htm#wp1015787
good or bad idea?
What you can try is to go into Device Manager, uninstall the devices that were installed before you installed the chipset drivers, then reboot, cancel the new hardware wizard, then install the drivers in the correct order. Sometimes this works, but most the time one has to start all over, reformatting, reinstalling Windows then installing the drivers in the correct order.