It does it for streaming, downloaded videos and music, it only seems to work for windows media player, but a few videos i have dont seem to work, and no i havnt tried that David but i will have a go
Goto control panel-sound-then try different settings under audio-the recent version of directx is causing some trouble with certain audio systems. Real player and quicktime also have a built in updater which runs at boot time, it could be the latest updates are not compatable with your system. I would uninstall each program and reinstall an older copy that worked. Then disable the autoupdating with start-run-msconfig in the window and uncheck realplayer and quicktime.-Maybe you will get lucky