DSCN is part of a digital camera industry standard for the naming of files (& folders). It is a naming convention and does not indicate the image/video file type and therefore does not show how it should be opened.
The image/video file type is indicated by the filename suffix (the bit after the
. at the end of the file name). For example,
DSCN0263.JPG is a JPEG image file.
DSCN0223.MOV is a .MOV movie file format used by many Nikon cameras.
(you could, for example, change the name of the above video file from DSCN0223.MOV to holiday.MOV without altering the video in the file or how it can be opened or edited)
In the case of .MOV files from the Nikon cameras (if that's what you are trying to open) then Windows Media Player and Apple's Quick Time should play them. They should also be editable in Windows Movie Maker.
If you are trying to open a different video file format please tell us the video file format and the camera that produced it.
