[Klutz Dohanger]

Download quick media converter from
www.cocoonsoftware.com
It will convert almost any media format, into
almost any media format.
...
Or, you could just download quicktime, but if
you’re not an apple fanboy/girl ... VLC from
www.videolan.org is the best alternative as a
player that will play just about anything.

[PeaceBeWithYou]

I tried vlc, I like Home Cinema better. Quicktime is about the last thing I'd ever recomend, just about anything is better.

I suggested the Nikon program because it has some nice editing features, and it is likely handy to the OP.