95 Merc

I have a 95 Mercury Grand Marquies and its been givin me some guff.
The car has a major wiring problem and i have not been able to locate
the source of the problem. The car wont run anymore, but when it did
if you hit the brakes the car would die. Same goes for the power
windows its like somone just turned off the key. I have checked with
the local napa and they hevent a clue so i turn to the combined wisdom
of everyone who cares to comment. Thanks a lot your help is greatly
appriciated.