Please Help With Video File Extension

[spidross01]

Have just received a file of a friend before he went on holiday, it was the first time really today i have looked at it, it has an .ogm extension. I believe it is a movie file, but have no way of being able to watch it, have looked at windows site help and says it is a vogis file, but am not sure, can it be changed into a windows media player file extension?

Many thanks for reading and helping