I recently were seeking a complete codec package for Windows enabling me (and especially my Windows Media Center ;)) to a) play nearly any codec and b) rip blue-rays to my discs so I do not always need to insert the fragile originals but can play them directly via streaming on my TV.
I found many tools and codecs but were missing an installing routine - consequently, I had to install them hand by hand and had to create registry key files for special settings I wanted to use.
During the past days, I stumbled upon http://shark007.net. The author of this side created a tool which even PEBKAB (Problem Existing Between Keyboard And Chair) can use.
It does work for both, x86 and x64 Windows Vista and Windows 7.
You may want to give it a try :)