Let's just clarify what the issue is first - that will help people give the right advice, or at least ask the right questions.
You are using GB-PVR on 64 bit Windows 7. You can watch live TV OK using your PC monitor and speakers, getting sound and video on all channels that you've tried. When you connect your PC to your TV, and watch live TV you get video OK on all channels, but only get sound on TV3.
Is that a correct summary of the symptoms?
Just one question for now - How do you connect your PC to the TV?
sudoko: Hi mate ! Yes, its all how you said , and my connection, pc-tv, is over HD TANK,similar like popcorn hour ! Thanks
In that case it sounds like the problem is your HD TANK - it can't decode the HE-AAC used by all channels except TV3. You could confirm that by temporarily trying a direct cable connection from the PC to the TV, if you can get them physically close enough to do that. However that probably is the issue, I know that only the most recent versions of the Popcorn Hour (A200 and C200) are capable of decoding Freeview|HD audio.