I've been playing on an Ubuntu machine recently which was not set to automatically update.  The following commands will acquire the updates and install them.  First run:

sudo apt-get update

You will be prompted for an elevated account password which will then be followed by a list of sites, sources and packages scrolling up your screen.  At the end, you should see "Reading package lists... Done" at which point, run the following:

I am frequently troubleshooting problems in a Windows Command Prompt.  There are some functions which can be tested at a very basic level.  For example, if I am unable to connect to a server via Windows Explorer, I might jump into a command prompt and try to ping the server. 

ping [servername]

The screen turns black, a popup appears and in the center of the screen you see: 

"You may be a victim of software counterfeiting."

Down in the bottom right hand corner, you see:

"This copy of Windows is not genuine."