You can use DirectX for that.
From the MSDN forum
//create the video
Microsoft.DirectX.AudioVideoPlayback.Video video = new Microsoft.DirectX.AudioVideoPlayback.Video(fileName);
//set the System.Windows.Forms.Control to play it in (e.g a panel)
video.Owner = panel1;
//Play the video (put this in a buttons click event)
video.Play();
//Pause the video (put this in a buttons click event)
video.Pause();
//Stop the video (put this in a buttons click event)
video.Stop();
Also check Playing Audio and Video Files Using C#
EDIT:
You may try this:
System.Diagnostics.Process.Start(@"yourfilewith a path");
to start the application.
A sample example:
String fileToOpen = "C:/test.avi";
System.Diagnostics.ProcessStartInfo ps = new System.Diagnostics.ProcessStartInfo("C:/Program Files/Windows Media Player/wmplayer.exe", fileToOpen);
System.Diagnostics.Process.Start(ps);