Would lights horn and door locks work if the computer is gone

would lights horn and door locks work if the computer is gone

Perhaps but there's more questions...
https://www.askmehelpdesk.com/cars-trucks/when-asking-about-your-vehicle-303903.html
Did these fail at the same time? Has this been diagnosed by a mechanic yet?

Most likely. Provide us the year, make, model, and engine and I might have a test to determine if your ECM is good or not.