[quote="gambit37"]1) I still can't get MP4 files to display in the preview pane movie player -- any solutions for that one?
2) Quicktimes don't play on my system at all anymore. I did have Quicktime Alternate but removed it. What's the best way of getting Quicktime support (you said QT made a mess of things so I'm not too keen on doing that again!)[/quote]
It's possible that your MP4 and/or MOV filetypes are just messed up. Here are the registry settings for both, from a vanilla Win7x64 machine:
mov_and_mp4.zip (1.06 KB)
For both Quicktime and MPEG4 (which are often the same thing these days, though there are areas where the two formats diverge), I just install an MP4 Splitter and the FFDShow codec. (There are links & instructions in Enable/fix playback of various media formats in Opus FAQ.)
That plays most MP4 files and most (new) Quicktime files; for the odd thing that doesn't play, I drop it on an alternative player with built-in codecs. Video software and file-formats are such a gigantic mess that it's futile trying to get every file to play in one program/setup. You can get most things working, and then with files which are encoded wrongly just have VLC and/or GOM around in case one of them can play the file. (And when none of DirectShow, VLC and GOM can play a file in a format that they should all be able to play, I just delete the file. 
)
If you install VLC, just be careful not to let it take over any filetypes as it can trash the registry settings that other programs/APIs depend on. (At least, that is my experience from the past. It may have been fixed/improved since then, but I've never trusted it with my filetypes since it trashed them once.)