What @PupnTaco is true. If you’re on Windows XP, the path to drag and drop your font files manually should be: your Windows partition, usually C: / the WINDOWS folder / the Fonts folders. If you’re on Vista, sorry I never used it and don’t know if the path has changed since XP.
Drag to this folder C:\WINDOWS\Fonts (at least, it works for me).
I do remember InDesign being a bit odd sometimes about sensing fonts and I think this has to do with its own built-in fonts (in Windows at least). I have never used it on a Mac and haven’t used it recently…
on vista: you can search for “fonts” in the “search for…” panel and your fonts folder will be found. Then copy the drive into the folder and indesign will add it automatically….