Here are step-by-step instructions for installing the Gentium Unicode font:
1. You must begin by downloading the Gentium font from the SIL Gentium Download page:
Please note the only the font named “Gentium” (or “GentiumAlt”) will work for polytonic Greek. There are several related Gentium fonts (“Gentium Basic” and “Gentium Book Basic”) that do NOT contain the necessary Greek characters. You want the main Gentium font.
2. Scroll down past the license and feedback parts of the page until you see the download options. Choose the Windows installer by clicking “Download ‘Gentium_102.exe'” (this will work for Windows XP, Vista, and Windows 7):
If your browser protects you from inadvertently downloading files, you may see a message at the top of the window. If so, click on the message and choose “Download File…”.
3. You should now see the File Download dialog. Click “Run” to install Gentium:
4. After the file downloads you may see another security warning. Click “Run”:
5. The Setup Wizard will now begin. Click “Next”:
6. Read the license agreement. When you are finished click “I Agree”:
7. You may now select which components of the product to install. Make sure that (at least) “Gentium Font” is checked and click “Next”:
8. Choose your installation location and click “Install”:
If you are installing on Windows 7 the default location will be different:
9. When the installation is complete, click “Finish”:
You should now be able to see the Gentium font in your applications that allow you to choose fonts.