I'm not a Windows guy, but on Mac, there are places fonts have to be placed in order for programs to recognize them. There are also font utilities that let you put your fonts anywhere, and the utility will activate them only when you tell it to. This is a good option, because having lots of fonts active that you don't actually need at the moment can use up processor power that could make your computer slower. I have a free program called Linotype FontExplorer X, and there is a Beta version for Windows here:
http://www.linotype.com/3321/freedownloadpc.html?PHPSESSID=9f11b13277f021fe87c02638915a2ba8
…but since I have no experience with this particular Beta, I can't say whether its good or not. Maybe someone else knows of some good font management for Windows (free or otherwise).
P.S. you should update to 6.52 to take advantage of all of the bug-fixes.