1. Remove a kind of codec pack (K-Lite Codec Pack, XP codec Pack and the like..)
=> It's the best solution for your PC
2. To avoid the codec problem in Windows Media Player, try VLC Media player.
- VLC Palyer:
http://www.videolan.org/vlc/
3. To avoid the codec problem in Windows Movie Maker, choose "Motion JPEG" video codec and "PCM" audio codec