Please HELP I have no clue as to what happened

[rmikeL]

I have a 1998 Expedition 4.6 with over 200,000 miles I recently had to replace the heater core but did not put in a new blend door, which is now not working. But that is not my main problem. I do not drive this vehicle much (poor gas mileage) but yesterday I needed to use it. So I put a charger on the battery, and charged it up making sure it took the charge. Started vehicle and started driving. I had gone less than 1 mile when I got three loud beeps from the dash, which was shortly repeated. Then the engine started to lose power. So I turned around and took it back home. It was then I noticed that none of the instruments on the dash were working. When I got home and parked it, I still had no instruments, nor would the dome light come on. I shut the vehicle off and now not only do I not have any dash but the only thing that now works in this vehicle are the power door locks. Will not start or make any noise, only thing that comes on is the anti-theft light which comes on weakly and slowly flashes. I do not have a clue what the heck happened. HELP

 

[Bedrck47]

get a meter and check your battery voltage or take it and have it load tested.
Before you get into anything else do the above.
Check all connections and grounds