I have had this problem 3 times now. This device becomes nothing more than a paperweight without WiFi. Dell wants you to do all the diagnostics via their website, which obviously doesn't work with this device when the WiFi breaks. You have to call support, get routed through 4 wrong departments, eventually talk to someone who knows how to solve the issue. The walk you through several steps and then reboot. It will then work for about a month, then you get to repeat the whole debacle. There is something wrong with the driver or the hardware that they need to remedy.
1.Go to search , type in device manager
2. Under Network adapters select the Dell wireless 802.11 a/g/n
3. Tap and hold, select uninstall
4. This will bring up a pop up window, make sure the box in this window is UN-checked, then select uninstall
This might solve the problem. If not you will need to uninstall several windows updates
Go to control panel/ programs and features and pull up the list of windows updates. The offending updates are:
Uninstall these and reboot. This solves my issue every time. Sometimes after the first step sometimes after the second. Dells response to when I asked how to keep this problem from happening in the future was to 'turn off the automatic windows updates'. This will ensure that the offending updates wont get downloaded again, but neither will any other updates. The problem is two fold, one there is problems with the device driver which is on Dell. The second is a problem with the windows updates being incompatible with the device drivers. This is on both Dell and Microsoft. The tablet is great, when it works, but this is a BIG problem that alot of people are experiencing. It needs to be fixed.