How to merge multiple video clips into one movie?

So, I have a handful of movies—maybe four or six in total—that I’m looking to play all at once on a single monitor or through a projector. They are currently in .mpg and .avi formats. Does anyone know of a specific piece of software that would allow me to merge these files into one single .avi file, specifically designed so they all play simultaneously on one screen?

Thanks so much!

Is it one on top of the other, or one after the other??

one on top of the other:
In Adobe Premiere, you just stack your clips in layers.
Or use Cinelerra (http://cv.cinelerra.org/about.php) on Linux.

one after the other:
Just throw them into a playlist in any media player—I’d recommend VLC, and definitely set the subtitles to bigger.

Side by side. Basically, I want to split my screen into four quadrants, with a different video playing in each one. All at the exact same time.

I tried to import four separate videos onto a single slide in PowerPoint to see if I could trigger them all to play simultaneously. There’s an option for it, but whenever I start the presentation, the screen just stays pitch black—even though I can hear the audio perfectly fine!
I usually handle all my editing tasks, like stitching clips together, adding transitions, and inserting subtitles, over in Pinnacle Studio, but I just can't seem to find a way to pull this off there...

Look, there’s gotta be an option in there somewhere—just dig through the help files for the split screen settings. If that clunky old Windows Movie Maker can pull it off, then Pinnacle has to have it too. It's just common sense, really.

I put this together using Adobe Flash.

Anyway, thanks so much for all the feedback and answers!

Benjamin King2 said:There’s gotta be an option somewhere—just dig through the help files for split screen. If that clunky old Windows Movie Maker can pull it off, then Pinnacle definitely should have it too.

You honestly can't believe 🤷
Pinnacle doesn't have that feature. 👎

I’m using Pinnacle too, and I totally had that same "where the hell is it?" moment when I couldn't find a specific option.

Comparing Pinnacle to Premiere is like comparing MS Paint to Photoshop.

With Pinnacle, you can just jump right in and start working immediately. It isn't exactly "smart" software—don't expect any bells and whistles—but it gets the job done.
Even handling two audio tracks is a struggle... let alone trying to sync up four different video feeds.