Video/Audio capture

I quite urgently need to get some good video and audio capture software found to record a graduation on thursday. I have tried both Blaze Media Pro and Camtasia 5 and neither has worked.

BMP refuses to record video at all and i cannot record sound because before i installed Vista i could select Stereo Mix as the audio source and it would record exactly what was coming out of my speakers but now i can only select either Microphone or Line In (dont know why i cant anymore).

Camtasia also doesnt work because i can only record audio from Line In or Mic (possible but sounds tinny and aweful!) and even if i set the video frame rate manually to 40fps it is still insanely low in the actual recording, actually impossible to watch!

Are there any programs out there that will actually record the audio i hear without needing to feed it back through a microphone (sounds really simple but so few programs do it...i really cant see why!) and record video at a watchable framerate (it doesnt need to be amazing quality as its a webcast of the graduation)?

Thanks in advance

Rich