Sometimes certain fonts won't show up in the C:\WINDOWS browser view, but will always show up in the Character map, regardless of it's type.
The exception to this, is if the file is corrupt. Mac/Apple OS fonts are interchangable with Windows, since a digital Font Type is simply a bitmap or vector (outline) file.
To see your Character map (in Windows 98, 2000, XP), go to Start>Programs>Accessories>System Tools and select Character Map from the list. Not sure of the path for Vista or 7, but it should be similiar.
Once open, you can view the various font types and the characters contained by way of the Pulldown menu. Once there, you can also see if the Font is a True Type (TT), an Open Type (O) or no icon for Meta Type/Postscript Font.
I have, at last count, over 120 fonts installed on this machine alone, and about 98% work perfectly on all of my imaging and graphics programs (some are specialized OS fonts for certain applications), all are viewable in my Character Map.