I've created a video with multiple video formats and they all run smoothly with the audio. However, I've also loaded in an avi file from Camstudio where I recorded my computer desktop. When I export to wmv and playback, all files are ok except the avi file which speeds up and the 8 minute video is over in around 30 seconds.
How can I get the avi file to slow down in sync with the audio playing so that it all lasts 8 minutes?

EDIT: Ok, so I've used Sony Vegas to change the file format to wmv and see if that changes it and it has. However, it's still running slightly faster than what it should. This time it appears to be missing the first five seconds or so which then puts it slightly ahead of the audio...