Both driver download files that you mention are for Dell wireless network adapters. Are you sure you don't have an Intel wireless network adapter?
Also, it ia absolutely essential that you install the drivers in the correct order. The Notebook System Software and chipset drivers must be installed before even attempting to install other device drivers.
Are you absolutely sure you have the Dell internal wirless adapter. There was a choice when you ordered. If you have the Intel internal wireless adapter (drivers on the same page under Network), then there is no way ever that the Dell drivers will install!!!
1. You could check your original system invoice (I know, you like thousands of other users have no idea where this important document is).
2. You could go to the following site, enter your service tag number, then click on the Original Configuration tab to get a very cryptic list of the components shipped with your computer from the factory
3. You could open the door to the wireless network adapter and look to see if it says Intel or Dell.
4. Since the Dell drivers won't install, you could make the assumption that it must have the Intel adapter and try installing the Intel drivers.
Geoff, since you have your service tag in your profile I pulled it up. Your system was ordered with the Dell Wireless 1370 (Broadcom) card, so it sounds like you were trying the correct driver.
You can request replacement reinstallation media for US purchased systems here.Dell Drivers & Downloads for all systems.
If you did not install the drivers in the correct order the first time, you may be better off reformatting, reinstalling Windows and then installing the drivers in the correct order.
If the notebook system software and the chipset drivers are not installed first, Windows will not be able to recognize nor properly install drivers for many devices connected to the motherboard. Thus it is ABSOLUTLEY ESSENTIAL that the drivers be installed in the CORRECT ORDER. You can try uninstalling all of the drivers you installed originally, then installing the notebook system software and chipset drivers, and then reinstalling the other drivers. My experience is that I can get this to work, but my experience is also that when I tell someone to do this on a forum like this one, it rarely works (probably because they don't completely uninstall all the drivers). Ultimately, most people have to start over and then install the drivers correctly after a reformat and reinstall of Windows.
So long as the Notebook System Software and chipset drivers are installed first, the other drivers can be installed in any order.