Blacked out screen and stuck with one application. package dnsutils 1:9.9.5.dfsg-3ubuntu0.1 failed to install/upgrade: package dnsutils is not ready for configuration cannot configure (current status `half-installed')

Screen blacks out sometimes. When you put it to sleep and wake it up, there is just one maximized window without the unity toolbar. Alt+tab etc. also doesn't work.
It last happened when I played a Youtube video.

This seems to be an issue with flash plugin for chromium.

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: dnsutils 1:9.9.5.dfsg-3ubuntu0.1
ProcVersionSignature: Ubuntu 3.13.0-40.69-generic 3.13.11.10
Uname: Linux 3.13.0-40-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
Date: Sat Dec 13 21:39:24 2014
DuplicateSignature: package:dnsutils:1:9.9.5.dfsg-3ubuntu0.1:package dnsutils is not ready for configuration cannot configure (current status `half-installed')
ErrorMessage: package dnsutils is not ready for configuration cannot configure (current status `half-installed')
InstallationDate: Installed on 2013-05-03 (589 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
SourcePackage: bind9
Title: package dnsutils 1:9.9.5.dfsg-3ubuntu0.1 failed to install/upgrade: package dnsutils is not ready for configuration cannot configure (current status `half-installed')
UpgradeStatus: Upgraded to trusty on 2014-04-22 (235 days ago)