I just fixed mine. I first suspected the little switch as the problem. I booted into bios with F2 and set the wireless switch to control "None". By the time it booted at bios exit it was already coñnected to my network.
My XPS M1330 was working fine until today.  While using the computer, it disconnected from my home wireless network. Windows Device Manager tells me the device is working normally.  The WiFi switch is on but the WiFi catcher doesn't find any networks.  I can connect to my home network with an Ethernet cable and my desktop, which is on the same network, can connect so i know its not my modem or router.  What to do?
My XPS M1330 laptop suddenly can't find any wireless networks.