After updating to Ubuntu 14.04, I installed Ubuntu restricted extras and then the Software Center crashed during the installation so I had to terminate the window. I removed and re-installed it and found that the MS fonts are not installed in my OS. Once in a while I'd get the bellow message (I've tried to re-install the MS true type core font package a few times but I still cannot see the fonts):

Data files for some packages could not be downloaded

The following packages requested additional data downloads after package installation, but the data could not be downloaded or could not be processed.

ttf-mscorefonts-installer

This is a permanent failure that leaves these packages unusable on your system. You may need to fix your Internet connection, then remove and reinstall the packages to fix this problem.