Depending on what part of the ecu is bad, yes.
No.
You must re-program ECU for your VIN
207 will not start 1.4 hdi above radio it says ecu fault
why won't my 2001 dodge ram van b1500 start it has no info stored in the ecu
No, the car will not start.
A good start would be to pull the engine codes from the ECU.
for ecu reset must disconnect cable battery for 45min and reconnect battery cable and start the engine
Sounds like water is getting in somewhere. A modern car usually has a brain, the ECU module. They are usually in the kick panels either side of the front footwells, or under the front seats or floor. This would be a prime suspect for ingress of water. If water shorts the terminals, it will show it's displeasure by giving up. I assume from your question, that the system recovers when dry. This would rule out permanent damage, by water entering the cylinders and causing 'hydraulicing'. Which is a bit more serious.
Computer Card? What are you talking about? There is no computer card in this vehicle. It has a ECU or computer as it is sometimnes called. Without the ECU the car will not start, as the ECU controls the fuel pump relay and fuel/air mixture. I doubt you can. The vehicle is completely depenant upon that "brain" for everything.
Yes, a defective ECU can cause a no start condition. They rarely go bad.
No. Anytime you swap ecu's make sure the numbers match and if you have the anti thief ignition or key with diode you will need to have the ecu reprogramed by a lock smith or dealer to get the car to start.