Conversion will depend upon the video codec used. In many instances, if it can't be played on the PC, it also will not be supported by any conversion app. This is because most media players, and conversion tools use the same codecs.
Open the file using gSpot of MediaInfo and check the video codecs that are used.
Also, video cameras typically fall into two categories: 1) they create video files using a standard video codec (which makes the files easily moved/played/processed on a PC) or 2) they create video files using a proprietary format. In which case they typically supply software with the camera for use on the PC. -- Google is your Friend