Synopsis:
How do I find out what version of Microsoft Windows or Macintosh OS X is running on my computer?

Solution:
In order to find out what version of Windows you computer is running, see: Microsoft Windows Procedure.

In order to find out what version of OS X your Macintosh is running, follow these steps:

• Click on the Apple pull-down menu icon in the top left corner your screen
• Select About This Mac
• Under the Mac OS X logo, there will be some text that appears as "10.x.x".

There are several possibilities that fit into one of the following categories:

• 10.5.*: release "Leopard" of OS X, officially considered Macintosh OS X 10.5
• 10.4.*: release "Tiger" of OS X, officially considered Macintosh OS X 10.4
• 10.3.*: release "Panther" of OS X, officially considered Macintosh OS X 10.3
• 10.2.*: release "Jaguar" of OS X, officially considered Macintosh OS X 10.2
• 10.1.*: release "Puma" of OS X, officially considered Macintosh OS X 10.1
• 10.0.*: original Macintosh OS X