A few days ago I posted a tweak for previewing audio files. Since then it suddenly dawned on me that the same applies for all formats supported by the mplay32.exe, including video - e.g. AVI, MPG, ASF, etc. - and CD audio as well.
So, here goes: If you want to quickly view a supported format audio/video file, and don't want to wait until Media Player loads, you can create a new action for these file types, called e.g. "Preview", with "C:\Windows\System32\Mplay32.exe" /Play "%L" as application specification. Oh, yes, that's in Explorer under Tools/Folder Options/File Types/Advanced/New.