cannot upgrade from 14.04 to 16.04

[Jimmy Au]

After fixing 3 errors with help in forum as solution below.

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 1397BC53640DB551

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 4E940D7FDD7FB8CC

sudo rm /etc/apt/sources.list.d/google-chrome.list
sudo apt-get remove google-chrome

I have no problems to run
sudo apt-get update
But, I cannot proceed to upgrade from 14.04 to 16.04

Ａｎｙ help to fix the upgrade.
Thanks in advanced.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.16.0-76.98~14.04.1-generic 3.16.7-ckt27
Uname: Linux 3.16.0-76-generic i686
ApportVersion: 2.14.1-0ubuntu3.21
Architecture: i386
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Mon Jan 23 05:27:11 2017
InstallationDate: Installed on 2015-07-18 (554 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release i386 (20150218.1)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2017-01-22 (0 days ago)
VarLogDistupgradeTermlog:

mtime.conffile..etc.update.manager.release.upgrades: 2016-07-04T08:21:14.897342