No sound on recorded TV

[mewnlite]

I just installed Windows 7 Professional 32 bit and am dual booting it and Windows XP. SageTV installed OK but I have had a few BSODs when trying to do channel setup. My present problem is that the recordings I have made aren't rendering any sound when I play them back. This includes Windows Media Center, Windows Media Player, Media Player Classic, GOM, and VLC. Other MPG files I have saved from the past *do* play with sound OK.
If I reboot into XP and play them, the sound is there in every player I've got. I'm assuming I'm lacking a codec, but I really don't know where to start. Any suggestions?

Motherboard - Asus P5N-D
CPU - QuadCore Intel Core 2 Quad Q6600, 2400 MHz (9 x 267)
Memory - 8 Gb (3.326 Gb in XP)
Video - PNY GeForce 9800 GT (512)
Dual-boot XP Pro SP3, Windows 7 Professional 32 bit

[VCRUser]

I get that fairly often - mostly on digital recordings, but it's always fixed by converting the video to another format - I usually use mp4 avi good, but occasionally DVD Extra long play. I like to do that anyway, since the shows play better on my older 'puter at lower bitrates (with no loss of quality that my middle-aged eyes can perceive). My other reason for converting is space-saving: when you record as much as I do and have such a huge backlog, even a terabyte drive can fill up.

[sdsean]

I had a very similar problem. . .
It seems to be some sort of decoder issue. . .

The cyberlink codecs are now protecting themselves from being used by sage, so that appears to be a problem. . .(i'm using power dvd9 on windows 7 64bit)

Instead of converting, i solved the problem by having my receiver set to stream direct from the coax spdif connection on my mother board to the receiver, and that solved it. . .