I looked up the update history of packages that have been update on Sat. 06/07/2014. A list is given below. After these updateds, the display driver stoped working as pointed out by the original post of this thread. At least one of these updates has affected display driver. But I have no idea which one/s of these may have caused the problem. looks like they are mostly open-ssl related updates. I would really appreciate if anyone could give a hint.
Start-Date: 2014-06-07 15:04:46
Commandline: aptdaemon role='role-commit-packages' sender=':1.65'
Install: linux-headers-3.2.0-64:amd64 (3.2.0-64.97), linux-image-3.2.0-64-generic:amd64 (3.2.0-64.97), linux-headers-3.2.0-64-generic:amd64 (3.2.0-64.97)
Upgrade: iproute:amd64 (20111117-1ubuntu2.1, 20111117-1ubuntu2.3), libknewstuff3-4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkdeclarative5:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libnepomukquery4a:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libgnutls-openssl27:amd64 (2.12.14-5ubuntu3.7, 2.12.14-5ubuntu3.8), libthreadweaver4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkdecore5:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libnepomukutils4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libktexteditor4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), linux-generic:amd64 (3.2.0.63.75, 3.2.0.64.76), libkmediaplayer4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkrosscore4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libgnutls26:amd64 (2.12.14-5ubuntu3.7, 2.12.14-5ubuntu3.8), libgnutls26:i386 (2.12.14-5ubuntu3.7, 2.12.14-5ubuntu3.8), libsolid4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libnepomuk4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkdnssd4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkparts4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), kdoctools:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libssl-dev:amd64 (1.0.1-4ubuntu5.13, 1.0.1-4ubuntu5.14), libssl-doc:amd64 (1.0.1-4ubuntu5.13, 1.0.1-4ubuntu5.14), libkidletime4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), linux-headers-generic:amd64 (3.2.0.63.75, 3.2.0.64.76), linux-image-generic:amd64 (3.2.0.63.75, 3.2.0.64.76), libkcmutils4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkfile4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkpty4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkntlm4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libplasma3:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkemoticons4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), kdelibs-bin:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkdewebkit5:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkjsembed4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkio5:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkjsapi4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), openssl:amd64 (1.0.1-4ubuntu5.13, 1.0.1-4ubuntu5.14), kdelibs5-data:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), linux-libc-dev:amd64 (3.2.0-63.95, 3.2.0-64.97), libkde3support4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libknotifyconfig4:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), kdelibs5-plugins:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkhtml5:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkdeui5:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libkdesu5:amd64 (4.8.5-0ubuntu0.2, 4.8.5-0ubuntu0.3), libssl1.0.0:amd64 (1.0.1-4ubuntu5.13, 1.0.1-4ubuntu5.14), libssl1.0.0:i386 (1.0.1-4ubuntu5.13, 1.0.1-4ubuntu5.14)
End-Date: 2014-06-07 15:09:08