I've just installed the new Windows 7 and am having problems with some .wav files not playing. The ones in question are information announcements (ie that anti-virus protection has updated) that are set up by non-Microsoft programs. The one I noticed first was when the Avast ant-virus protection program updates it announces it with a sound message. These won't play in Windows Media Player but will play in VLC Media Player. I've tried changing the default player for .wav files to VLC but I still don't get the verbal announcement. My previous OS was XP and I had no problems with these files in that system. Thanks for any advice.