uninstall via add/remove programs

scan your system with sherlock, this will show you broken codecs nice and easy. also file locations

CodecTweakTool will allo you to list codecs and remove the dodgy ones. this will most likely only remove the registry enteries hence why you need sherlock to find the files and remove them

directshow filter manager (which is also what this groiup of softeware is called) should be able to find and remove codecs in one go but it does not seem to work properely. but worth keeping for refernce.

shark007 - uninstall old version first. for x64 install 32-bit and then 64-bit

klite possibly has a codec repair utility where it removes old knakered ones etc ..