PLease help! no sound only when playing games

[i.tommo]

My sons pc
xp2500
asrock ks741 onboard cound c-media
ati all in wonder 9800 pro
512mb ram
etc etc
sidewinder gamepad

the pc was playing games fine yesterday and films ok with sound, today i installed omega drivers 5.1 catalyst driver and the all in wonder control center i got the tv working and capture all working fine, but now i have no windows sound or games sound, i have the AIW sound output into the line in on the mobo. all the sound,game drivers are all installed in the device manager and all volume levels are up,

any ideas please my sons doing my head in

cheers ian
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edit:

tried an old cleative labs soundblaster live card in and set that up ok,

now ive got sound on games, windows dvd player but not on my ATI tv display, ive tried the audio outout from my 9800pro in all the creative ports but still no sound, at least my sons stopped moaning but would still like to get the tv sound going.

cheers ian