help with power dvd

[Acgrundy]

ok so I have power dvd version 4.0 and I am running XP

when I have a file such as an m2v and I choose open with...

then I browse to the power dvd and select it.  it does nothing, it won't show up in the list of programs after I have selected it.  I can open up power dvd and play things fine with it by opening them up in power dvd, but I can't double click a movie and open it with power dvd. 

any help?