Ok, this might be useful for people.

When I used Chrome in Ubuntu 12.04 when I went to watch a video on youtube (and then any similar site) an error message of couldn't load plugin.

After re-installing Chrome which didn't work and checking around previous threads etc, I went into Tools-Task Manager noticed the Plug-in Shockwave flash was N/A.

I then typed chrome://plugins/ in the address bar, extended the libpepflashplayer and disabled /opt/google/chrome/PepperFlash/libpepflashplayer.so

And then it worked again?

Anyone know why? It was fine until tonight.