I know this is going to sound a bit confusing, so I will try to say it as simple as possible.
WMV/WMA 1 & 2 is handled by FFmpeg for VLC. WMV3 or HD and WVC1 along with multi-channel audio is handled through the Windows dshow codecs.
The best bet when trying to play any of these files is press ctrl i and then the Advanced Information tab and look at the formats.
The easiest way to get the codecs is to install the latest version of WMP 10 (WMP 11 Beta is NOT recommended).
For Windows 9x - Me try installing the Windows Media Format SDK package.
For XP users that want WVC1, the addon can be gained from Microsoft by searching WVC1DMO and downloading the encoder/decoder package.
