PHP encountered an Access Violation
Just thought I would share this one with everyone in case they get the same problem.
Last night the server automatically installed an update and rebooted, this coincided with someone trying to webcopy my photopost directory.
This morning when trying to acceess the photopost directory I got the 500 error "PHP encountered an Access Violation ...." and couldn't access any documents. However for other php documents the system worked fine.
I did all the usual stuff, restored the database, restored the photopost directory, restarted mysql, restarted IIS.
In desperation I hit the power button and restarted the server and hey presto everything back to normal. What I would have done if the machine wasn't in the room next to me and it was on a shared server somewhere remote I do not know.
Still not quite sure what the problem actually was but have changed the automatic updates to notify me (so I am present and can address any problems at the time).