You have videos in many parts. So no problem, you can make them become one whole video very easily.
You will need the Virtual Dub software.
Link to download : http://www.virtualdub.org/download.html
To start you should run VirtualDub and open the first part.
DO: File>Open>Browse for the video>Open
Note: if you want to mix two parts, they should be of the same frame rate.
DO: Clik on video > Frame Rates.
A window will appear and will show you the frame rate in fps.
Now click on OK and you can close the window because there's no change to be made.
Setting the parts
Now you open the second part like you did for the first one.
Click again on video then frame rates:
If the frame rates are alike so its fine, there's no change to be made.
And if the frame rates is different from the first click on change and input the value. For example if the first part was 25.000 fps just change the second one to the same value and then click OK.
Now to save the just click: FILES>SAVE AS.
Note: If your video is more than two parts just restart the steps for each parts and check if the frame rates are corresponding.
Bond the parts
Now that the videos are correctly configured, open again the first part.
Then open the second to mix.
Do: FILE > ADD AVI SEGMENT. Then do the same to the other parts.
Click on video and choose direct flux copy
Just do the same thing in audio setup.
So now you just have to save your new video:
FILE>SAVE AS AVI.