type cmd and press enter. this will open the command prompt.
In the command prompt, type
copy /b "D:\video1.flv" + "D:\video2.flv" "D:\FullMovie.flv"
where the video1.flv and video2.flv are the video files to join and fullmove.flv is the resultant combined file.
You can specify any number of files to join.
Also notice I have typed the entire file path in the above command.
Press enter and the files will be joined.
