Here are a few things I have had work on a couple of laptops at work:
Successful Method 1:
If you are not using the HomeGroup, disable IPV6.
Successful Method 2: Install the updated drivers from the website of the Adapter's manufacturer(i.e. Intel not Dell).
Successful Method 3:
Delete the network from the list in the Network and Sharing Center and then manually add it through the Manage Wireless Networks in the N&S Center.
Successful Method 4:
Disable the IPV6, save the newest driver to your desktop, uninstall the adapter and make sure to check to have the driver software removed as well. Now go to the Network and Sharing Center and remove your wireless network from the saved list .After you have done that, go and add it manually. Then, scan for the changes and the adapter should be reinstalled with the old driver as the main. THEN, go and install the newest driver.
Method 4 is the only way my Dell Studio 1537 would work with the installed Intel(R) WiFi Link 5100 AGN. On a side note, I just tried method 4 tonight after the Microsoft Virtual WiFi Miniport Adapter showed up in my Device Manager.
I hope this helps!