[header] How to merge avi files [title] Download virtualdub from the sourceforge website and install it on your computer. [title] Open a video file in virtualdub by running the software and then clicking on " open " from the file menu. [title] Browse to the first avi movie clip that you want to add and click " open. 
[step] " you have just added the first avi file that you want to merge in virtualdub. [title] Drag the timeline slider to the end of the first clip.