A - The easy way to install a font is to just Unzip/Extract the font file(s) to the \Windows\Fonts folder.
NOTE: The font(s) may not show up in a program's font list right away, you may need to Refresh your computer. On your Desktop, just Right Click and in the menu that appears, select Refresh (or you can just press F5). If all else fails, just restart your computer.
B - To install fonts the "proper" way, do the following:
1) Open the Run Command Window by either Pressing the Windows Key + R -OR- Click on the Start button and select Run...
2) In the Run Command Window, type in "%windir%\fonts" and click OK. This will open the Windows Fonts folder.
3) In the Windows Fonts folder, Choose File > Install New Font.
4) Next, locate the font(s) you want to install. Navigate to the font(s) by selecting the Drive then select the folder the font(s) are in (make sure that the fonts are unzipped first). Once you're selected the Drive/Folder the font(s) are in, they will appear in the List of Fonts.
5) Select the font(s) that you would like to install. To select more that one font, Press and Hold the CRTL key then select the fonts you want. If you want to select all of the fonts in the list, just click on the Select All button.
6) Before clicking the OK/Install button, make sure Copy fonts to Fonts folder is checked. Now you can click on the OK/Install button. Now the font(s) are installed.
NOTE: The font(s) may not show up in a program's font list right away, you may need to Refresh the Fonts folder. While you are still in the Windows Fonts folder, go to View > Refresh (or you can just press F5). If all else fails, just restart your computer.
C - If for some reason you can't get a font to install or you just want to quickly use a font, you can install the font temporarily. Just go to where the font is located and Double Click on the font file (.otf .ttf and/or .fon) and the font will open into the Windows Font Viewer. If you have other font viewing software installed, Double Clicking on a font may open that software instead, so instead on Double Clicking the font file, Right Click on the font file and go to Open With > Windows Font Viewer.
When you have a font opened into the Windows Font Viewer, it acts as if it were installed but only when the Windows Font Viewer window remains open (you can minimize it if you want). If you close the Windows Font Viewer window, you can no longer use the font unless you re-open it or install it. If you used the temporary method and saved a file using a "temporary" font, the font will not be displayed properly unless the font is re-opened into the Windows Font Viewer or installed.