Bose rear speakers not working

Hi,
I have bose speakers and running windows vista on my PC. When i play anything on my dvd or HDTV, my rear speakers don't work. It was working fine earlier. Connections are OK. But still its creating a problem. Can someone help?

Thank you in advance.

Connect all the audio cables directly into the receiver. Don't use the optical out on the HDTV, it will only provide stereo which may be causing your rear speaker problem.

Get one new sound card compatible with vista. Try to enable EAX in the audio settings and select stereo which will play all the speakers. Also unmute youe PCM card and headphones in the mixer. Turn on matrix mode to enable surround sound.

Try this:

• Right-click on taskbar speakers
• Go to playback devices
• Then properties
• Then go to enhancements
• Enable Environment (ROOM) and Speaker fill