Cannot record video or audio in ON2007

[h4rrydog]

Hi. For some reason, I can't record audio or video notes in OneNote
2007 anymore. Every time I try, I get an error dialog box saying "At
least Microsoft DirectX 8.1 and Microsoft Windows Media Player 8 are
required to record sound. Install both programs from the Download
Center on the Microsoft Web site, or reinstall them and then try
again."

I used to be able to record media clips in ON with no problems.
Unfortunately, I don't know what changes to my system broke this
function as I only just recently discovered the issue when i tried to
record a sound clip a few days ago.

I am running Windows Vista SP1 and Microsoft OneNote 2007.

Vista comes with DX10 and WMP11, however there doesn't seem to be a
way to reinstall these programs without reinstalling the whole OS.
I've tried sfc /scannow, but that didn't seem to have any effect on
the problem.

WMP works fine on its own, playing audio and video just fine. I don't
have anything that requires DX10, but dxdiag seems to indicate that
everything is fine.

Can't for the life of me figure out what's going on. Please help!