Well all you do is Load the First File into Virtual Dub then go to "File" to "Append AVI Segment" and Load in the second part of the AVI File, then Make sure that Both audio and Video are set to "Direct Stream Copy" then go to "File" to "Save AVI" and that is it...Remember to join 2 Files in V-Dub both Files have to be the Exact same Format, meaning Audio Format and Sample Rate and same Frame Rate and Resolution and Codec...Cheers