Check the master switch on the drivers side door, sometimes it locks up and will free if you fiddle around with it, if it doesn't it may need replacing, wouldn't be a bad idea to also check the fuses.
It could be that the torque convertor is locked and not slipping which it should do as the normal operation
the transmission that is in a 1996 f150 is a 4r70w if automatic
if you have keyles entry the battery in the remote might be dead which would mean you would need a new one
vacuum leaks
emergency blinker
I believe that is an E4OD automatic transmission
Inside the automatic transmission pan
automatic hubs never trully lock in the simple turning force of the drive axle locks or splines a series of "locking" dowles or teeth together usually they break very easy and ther replacement kits offerd by warn are comparable to oem
Manual choke
Try local parts stores, local junkyards, or local dealer.
That would be the Ford F-Series pickups (F150, F250 so on and so forth) The XLT was a package that had power windows and locks (conscidered a premium package)
C6 or an aod