How to change a .flv video file to view in WMP;

I have this small video file I got from online (nevermind what it is), it's
just that I need to figure out how to change it from .flv to .wmv; but I
think I do not have the right or enough codec's on my pc (I have WMP 10,
don't want anything else). I need to 'have my WMP's back', and to do so, I
need to give it what it needs to play what I want; right? Fine. I can change
the file's extension to .wmv, BUT, WMP doesn't have the right amount of
codec's, misc, nor (installed stuff) on my pc, to be prepped and ready for
me, whenever I need it to be. I'm good techie, but not that good.
(please be direct, to the point and know your
stuff . . . thank you).
--
I''m either away from a computer right now or ''in the field''. Meantime,
feel free to visit me on my website: http://www.jeffreydavidmorris.com Thank
you again, and have a nice day.