Look at the buttons at the end of virtualdub, the last two mean start and finish and you can select areas of the movie with them. you can then simply go to file-save avi to save the part you just selected.
Thanks this has helped me a lot, but now I have another problem. When I wan't to compress the audio the program asks me which to use. I clixk MPEG layer-3 and then I'm asked what to use, 56kBit/s,... how can I know which to use since the bitrate speed of most of my movies isn't in the list. Thanks, xackitt.
VirtualDUB would already know what your audio is! Compression is just what they will convert it to because like if you want compression then they have to compress it using something! Right that sounded a bit weird but I don't know what other way to say it!
