Beginning last week, my Inspiron 17R N7110 can ONLY connect to the internet if my Apple iPod Touch (2nd generation) is connected. As soon as I turn off Wi-Fi on my iPod Touch, my laptop's internet stops working, with the message "Default gateway cannot be found". I have no idea how my iPod is affecting my laptop's internet connectivity, so how do I fix this problem?
Try using Last Known Good Configuration (instructions here) or use system restore to restore your computer to a time before you had the problem (instructions here).
Windows Reinstallation Guide and Related Wikies See here for other wikies such as Customising and Using Windows 8.1, Dell Wireless Cards and Unofficial Drivers.