I wouldnt advice installing a "all in 1"-codec pack.
It has been reported multiple Times that these codec-packs sometimes fuckup other already installed codecs.
For instance Xvid-codec or Nvidia-dvd-codec if already installed.
Best way is always to use Gspot (free spamfree tool)
http://gspot.headbands.com/ to determine what codec the movie wants, and then get and install exactly and only that codec.
The easy "all-in-1" way can work and aswell mostly does, but there is a chance you messup your System !