car had complete electrical overhaul.....ecu,bcm, fuse box
electrian thinks the engine has seized. what is the quickest and easiest and cheapest fix to my problem. would a tune up and engine flush help or do i need to rebuild?

 

No, a tune up and engine flush will not help.

If water got into the engine, remove all of the spark plugs and see if the engine will turn.

It should turn. If it doesn't, you will probably need a new engine.
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I discovered your other posts on this problem. In one you said that the car would crank before you replaced all the electronics.

It sounds like you have some very serious problems with your car. You are not going to get the answers you need on this forum. I recommend that you find an expert mechanic that can look at your car and run the tests you need.