For Windows Vista this is the procedure; you install new fonts from the Font Applet in the Control Panel.
Windows Vista
1. Select "Control Panel" from the Start menu
2. Select "Appearance and Personalization."
3. Select "Fonts."
4. In the Fonts window, Right Click in the list of fonts and choose "Install New Font."
5. Navigate to the folder that contains the fonts you want to install.
6. Select the fonts you want to install.
You can click to select one font, Control-click to select several fonts, or Shift-click to select a contiguous group of fonts.
7. Press the "OK" button to install the fonts.
8. Close the Fonts control panel when you are finished.
9. The fonts are now installed and will appear in the font menus of your applications
Please note: Earlier Windows versions allowed "drag and drop" of new fonts into the fonts folder (Usually located at C:\Windows\Fonts)
I'm not sure that will work in Vista but you can also try that.
I hope this helps. If not please post again for clarification.