How can I Export movie with audio

I had finish up editing my composite... But when i render it, it has no audio. Audio Output under render options is not ticked and i am not able to tick it. What can i do to fix it?

WINDOWS VIDEO FILE. NO COMPRESSION.

You are telling me that i cannot build a DV FILE with audio or avi file no compression with audio? I want full quality for this. And my footage had audio before i import to Combustion. Now i can't tick the audio option in under rendering. Why?

When i open my video is there any seeting to adjust to make it see that it has audio or all of that is automatically?

Because when i render the movie i believe the audio box should be ticked already by default.

even your original footage had audio, on import (or open for that matter) the audio is stripped.
go to the audio tab and import the audio (by obviously choosing the original video which containing the audio).
then, after importing the audio, indicated by a waveform in the timeline, you can tick audio on in the render settings.
as long as you don't render to an image sequence, almost all video codecs will serve you.

best,
-rayk

p.s.: pressing "f1" will bring up the help files which might give you a much faster answer to some of your questions