I have a Dell Latitude E6540 laptop with a Intel core i5 CPU, 8GB ram and 1TB disk. It has an Intel Centrino Advanced-N-6235 network adapter. Every time I turn on this laptop I have no wi-fi connection. I have to go through the whole process of opening and Internet Settings and going to known networks to try and connect to the internet. I type in my key for the router and hit connect and nothing. "Cannot connect to this network" I click on troubleshooting and go through the whole process to get a message that I don't have a valid ip address or a network cable is unplugged. Now I am sitting in my living room and I am literally 15 feet from the router and modem. Most of the time unplugging the router and resetting it usually works and I could get on the internet. I have checked for updated for the router, the modem and my network card and there are no updates. I have checked with Intel for any updates and there are none. I also have 4 other computers, 2 laptops and 2 desktops that have no problems at all connecting to the internet, so I figure it is not the router or the modem. It is this laptop. Can anyone help with this problem?