The Greek language, together with many other languages is part of the Windows Operating Systems, however it is not enabled by default. All these languages apart from English need to be enabled for a user to be able to read and write using them in Windows.
You can connect to this Wiki page to see the steps on how to enable Greek fonts in Windows.
Older versions of Windows
For older versions of Windows, like Windows 2000 or XP up to Windows 7, you can follow the instructions we compiled into a document here:
Greek spell-checker for MS-Office 2010
In order to be able to spell check documents and other files using Office 2010 you can download the ‘Greek Language Pack’ from this page and install it (after you download it, just click twice on the file and the installation procedure will start, its very simple)
For Zenon Education Centre