If you wish to install a particular Font in Windows Vista, it is not just enough to copy-paste it in the Fonts folder. You also have to register it. To install fonts, you may follow the following procedure.
Install new font
Open Control Panel > Appearance and Personalization > Fonts.
In the left pane, the right click on the Fonts folder and choose Install New Font, to open the add Font dialog box. Navigate to the folder where the new font is located and select it. Click Install.
If you uncheck the Copy Fonts to Fonts Folder box, it will save the space on your hard disk by using the fonts from their source location itself.
To uninstall a Font, select the particular Font, right-click on it and simply choose Delete.
Font not working
If in spite of installing a font, you are unable to see it in the fonts menu of the program, you may have to check whether that particular font requires you install two files in the same folder; a bitmap file for the on-screen font, and an outline file for the printer. The bitmap file might be missing. Try contacting the font creator to see if there is a bitmap file you can install. If there isn’t a bitmap file, you might try using a different font.