>Sorry that I cannot type Chinese Big5 code. (BTW, can you read Chinese GB code here?)

I could read (some simple) Simplified Chinese.

>I try to record sound from WAVE when I play other movie files. The sound is good. So, my sound card may not be that bad.

No, the test you did isn't ust the ADC(Analog to Digital Converter) on the sound card. It's just digitally copy the sound with distortions like SRC or VOLUME adjusting when you want to record from a WAVE source.
But when recording from tv wonder, the sound is transmitted analogically by the cable you link between tv wonder and your sound card and is digitalized by the ADC of your sound card. If the ADC of your sound card is not good, the recorded sounds simply noisy.

>onboard C-Media CM8738 Audio.

In my opinion, it's not a good sound chip in recording quality because all the digital and analog circuits are in the same chip. And most on board sound is worse than PCI sound cards using the same sound chip.
Most modern sound cards use external DAC and ADC chip with their (digital) sound chip, this kind of design can reduce noise.

>While I failed to record sound from TV >Wonder. The sound recorder told me that
>" Failed to open waveform input device.
>Please stop other audio applications and >make sure using correct format."
>No matter which device I use (I tried Line >In, Aux In, CD In, Wave.), I just cannot >record sound from TV Wonder.

I don't really know why this happens. But most commercial sound cards can do only one recording task a time. Therefore only one program can recording sound at the same time. If MMC is recording (even it isn't save the recorded sound to file), you can't do this with your recorder program.

>Thanks for your answer!