Pretty please?

Please don't ever force x64 MPC-HC/Filters on a x64 OS/system again, OK? I had to thinker with this bullcrap until I found out that 10.9.0 installed the 64 bits version of MPC-HC when I made a direct upgrade from an earlier version, making some videos play only the audio (using MadVR, by the way).

That aside, thanks for always keeping the pack up to date.

It installs both 32-bit and 64-bit version. It uses the 32-bit version by default if you select madVR as preferred renderer during installation. During installation you can also choose for which player to create file associations and thus which one is used by default.

The default player can also easily be changed after installation by going to the "Default Programs" settings in Windows.

The 64-bit MPC-HC should be able to player pretty much everything, so your problems should be solvable. What kinds of videos are you having trouble with? You can check with MediaInfo what kind of video they contain.