Electrical Problems

Approximately 4 months ago while driving all my dash lights came on "battery, brake, VSC, ABS, Tire pressure & check engine" also my digital odometer showed an "E" where the temperature would normally be. I pulled over and shut off the car only to find that when I tried to start it back up it would not start, would make not a sound. After waiting a while I turned the key and it came back on. This was periodically happening and was very disconcerning because when it happened the following things would not worK: blinkers, windows, radio, heat / AC, heated seats, only the dome light would work. What I also found is that if I stopped the car and put it into park the car would not allow me to take it out of park unless I shut the car off and waited a while for it to start back up again. On one occassion I had to have it towed because it would not start back up and when the tow truck driver hooked his monitor up to check the computer it was not even registering that I had a computer. When I took it to Toyota they replaced my computer that I paid for almost 2k for because they said that was the issue and nearly 1 week after having the computer replaced it was happening all over again and has continued ever since, they toyota guys seem baffled as to what the problem is so I feel pretty desperate, if they dont know then who the heck would? I stopped by Toyota the other day while this was happening and the guy tested the computer while it was happening and again said that the computer was not even registering? Please help!