This morning's update broke my CentOS VB VM

[MR ZenWiz]

Four days ago I ran my CentOS VM (in VirtualBox) and updated it.  I
only use it occasionally for experimenting with KDE, so it's been off
since then.

Today there was an update for Maverick (not the upgrade to Natty), and
now my VB CentOS VM won't run, claiming that there's a hardware
discrepancy and it can't find the video.

My VB Windows VM does not have the same problem.

So what broke?