AC3 codec killing WMP9 sound

[Pavlov]

I was unable to get sound from an Xvid-AC3-HLS file using AVI preview in K-Lite. Gspot came up with the missing codec - AC3 - which I installed. Now I can get sound from AVI preview but when I try to playback TV shows recorded with Compro PVR I get no sound from WMP9. So I uninstalled the AC3 and am back to square one -sound in WMP but no sound on Xvid.
What's the solution?
What about FFDSHOW? Could it be a solution or could it make things worse?
Thanks

K-Lite 2.4.3
Clone DVD
Any DVD
Nero Burn 6
Power DVD 5.0
Divx 5.11
WMP 9
Compro PVR