Ah, allow me to clarify.
Insert your text. Highlight it. Without doing anything else (text box still has active borders, etc), click on the font pulldown to open it up. Choose a font. Your text should change to that font. Now, that font should be highlighted, but the pulldown menu disappears. Try using the arrow keys to see if your font selection changes, therefore altering the highlighted text.
I have PS 4.0 here, but my personal license at home is PS 6. I just did it last night so I am going on memory. It might be that it just won't work for you, especially if you are on a mac, but it works fine in most apps that have pulldown font menus, at least for me.
I do hope this helps as I know how bad it can get tryin to grope blindly for a font... "Absorb what is useful, discard what is not. Add what is uniquely your own." - Bruce Lee - The Tao of Jeet Kune Do