Thanks friends! Problem solved.

I rushed home for lunch to check things out and everything was snuff except that the global quality setting in the fog and haze room had been knocked down to -7 of all things. i never suspected.....either there's a ghost in my machine or I'm completely senile with multiple personality disorder or...just plain daft lol....

At any rate, I know what to keep my eye on now and we're back in happy render land.  Thanks again for the replies......they always help!!!

Have a good one!

Happy Monsoon