From the "Start" menu select "Control Panel" and then select the "Appearance and Themes" category. Switch to category view if necessary.
Select "Fonts" from the "See Also" panel at the left of this screen.
On the "File" menu, select "Install New Font..."
Click the drive and folder that contain the fonts you want to add (Where you saved them to).
To select more than one font to add, press and hold down the CTRL key, click the fonts you want, then click on "OK"
Open the Windows Control Panel
(START > SETTINGS > CONTROL PANEL)
Double click on the "Fonts" icon in the Control
Panel
(a new window should open and you should see all the installed fonts on your
system)
Click on the "File" menu and select "Install New
Fonts"
(a new window "Add Fonts" should pop up)
Locate the folder on your hard drive containing the fonts
Double Click on the font file you wish to install
and click on the "OK" button
Mac/ Linux etc.
If you're savvy enough to have a Mac or use Linux, etc, I reckon you know how to install fonts - I haven't a clue, sorry!