When I view a video, I am unable to zoom in/out (icons grayed out). Changing the size is impossible (grayed out). It did not use yo be that way. What can (must) I do to be able to regain these features.
Thanks
You're probably no longer using the Opus movie plugin (for that type of video file at least) and instead falling back on Windows Media Player or another viewer (via the ActiveX + Preview + Office + Web plugin).
If the Opus movie plugin is enabled, but not playing the file, it usually means a video codec or splitter is missing for that type of file. Note that the Opus movie plugin requires 64-bit codec and splitter DLLs, while a lot of video players use 32-bit ones. If the 32-bit and 64-bit DLLs are different (which is fairly common) then it can mean some formats play in some things and not others, and can usually be fixed by working out which DLL is missing and installing it.
Is it happening for all movie types or just some?
If we're talking about the preview pane (not the standalone viewer), there should also be an indication of which viewer is being used to play the video, above the video and next to the filename in the viewer pane's titlebar. That detail may clarify some aspects of what's going on.