14.04.1 hangs during videos

[MR ZenWiz]

I'm running Xubuntu 14.04.1 with the latest nVidia driver for my
system, and tonight the system froze three times while playing videos
- two in Firefox and one in mplayer.  Froze as in totally
non-responsive other than the reset switch.

This is not the first time - it has also hung in videos via Chrome and
VLC,possibly xscreensaver, too.  (Light Locker was worse.)

What is it with the video interface in 14.04?  I never had this much
trouble with 12.04, back to which I am seriously considering going.

It was better a week ago, before the last X-related update.

Frustrated,
MR