I'd suggest you just forget K-Lite Codecs and install something that works like Shark007's FREE Codec solutions
. These work very well on Windows 7 64-bit systems.
The instruction pages on Shark007's web site are a real pain to read and decipher but there is a very good forum / help section which solved all the problems/misunderstandings I ever came across. Just don't forget to uninstall all other codecs and set your User Account Control to default before installing the Shark007 codecs.