Soooo.....I received a Dell E7440 from my company. I have had the same issues as everyone else. Updated all the drivers and software etc....Nothing. I even let windows manage my wireless settings versus the Intel application. I noticed a bit of a battle between the 2. I saw the suggestions to run a repair on the Intel application and I tried to do that but inadvertently uninstalled it instead. Whoopsie!! It has worked flawlessly since the moment the uninstall was complete. I have pinged the heck out of yahoo with zero loss. I think I used to get about 50 pings before it started failing and resetting the wireless hardware.
PS - I don't recommend dropping to TKIP just because it works. I didn't read all the messages so I am not sure if this was resolved. Sorry if this is repetition.