Nero showtime 3 no audio Please advise

Hi

i have Nero 7.5.7.0 and Nero showtime 3 installed

i get audio with many files , but this 1 file in particular ,

but showtime is the only app that will play the video

smoothly and properly .

Other progs that cant handle the video stream are Cyberlink

power dvd deluxe version 7.3 , VLC media and windows media

latest updated version as well .But they play the audio track .

i have an AMD 2600+ , Gigabyte MOBO GA-7N 400 P2 with just

over 1 gig of memory . A dvi2hdmi cable to my TV

The specs of the file i want to play are as follows

(WMV-AVI)

Video Format.........: WMV3 (in AVI container)
Resolution...........: 1280 x 720p
Aspect Ratio.........: 2.35:1 (OAR)
FPS..................: 23.976
Source...............: 1080i cap (thanks to poster SCI-FI)
Audio:...............: English AC3 (Dolby Digital 5.1)

Can anyone please advise me further on this ?

Cheers