1. Select the font files (they should be truetypefont,openfont, a file like that)
2. hit "edit" "copy"
3. Open control panel
4. Open "fonts" folder
5. Paste Font files into font folder ( a little bar should show up saying loading "insert font name here" font )
Tada! done. Note that most programs need to be reopened for the new fonts to appear in the font menu.
Dafont is a great resource.