Help, lost vdpau and opengl output after accidentally starting chromium as root

[Arthur Marsh <arthur.marsh@internode.on.net>]

Somehow I tried to run chromium as root last night and now chromium 
brings up a window, but with the window only showing the existing 
background and not actually doing anything.

see: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=793748

It is also difficult to quit chromium except by a kill -9 of the main 
process.

A clue appeared when I was unable to run vlc (which uses vdpau by 
default) or mpv (which uses opengl by default), getting the same 
unresponsive windows.

Once I moved the vdpau libraries out of the way, mplayer ran ok using vx 
and vlc ran ok (using xv?).

Where would I look for what was broken and what files might need to be 
reinstalled?

KDE is mostly at 4:4.14-2-5 here.

I'm happy to supply any more information on request.

Arthur.