for adding a font all u gotta do is download to C:/Windows/Fonts
but to activate em usually my little trick which works for sum reason is to go to the folder and select the font wit ur mouse(click on it) and drag it around for like 2 seconds ... then it should show up in word photoshop etc etc
-nate [dont ask me taco ]
nate you suck :P it's actually going into control panels, then fonts, it'll automatically load all the fonts you have in there, then just start PS, if you already have it started... well... restart it