keyless entry system

2003 Explorer keyless entry system, no number on door, just key fob.  Exited vehicle
and used fob to lock.  Upon returning when trying to unlock vehicle would unlock then
immediately unlock.  Finally used key to gain entry, vehicle started and proceeded on.  
Upon entering vehicle again, (with key) inserted key and dash instruments began
jumping every back and forth, vehicle would not start - dead key.  Disconnected
battery, reconnected and vehicle starts as usual.  No jumping instrument panel either.  
However key fob will not operate at all.  Tried to reprogram fobs by using the on-off
eight times in ten seconds procedure and vehicle will not enter program mode (no
automatic lock/unlock) signaling mode has been entered.  Any ideas?