Re: Problem with Apache2 after upgrade from Ubuntu14.04 to 16.04

[Marat Khalili <mkh@xxxxxx>]

> Given where I AM what would you suggest would be the best course of action to get back to a working system please?

As was already suggested, run:
  sudo netstat -tpln
to see what program occupies port 80. Also try:
  ps -AFH
to see if other instances of Apache are already running. Compare their PIDs with those reported by:
  systemctl status apache2

If you don't know how to interpret the outputs post them here.

If you already established that e.g. nginx is to blame, decide what to do with it, e.g. daisy-chain web servers, bind them to different IPs or leave only one.
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With Best Regards,
Marat Khalili