The Microsoft Windows Vista operating system support for Windows PostScript fonts is limited to those that include PFM files. Please note, not all Windows PostScript fonts include PFM files. If you are working with Microsoft Windows Vista, we recommend purchasing OpenType or Windows TrueType fonts. If you do need to purchase Windows PostScript fonts for use on Microsoft Windows Vista, please reference the "Font File Names Included" section at the bottom of the product page on Fonts.com to determine if a PFM is included. If so, the Windows Postscript section will list a file with a ".pfm" extension.