when you get something like your photo on screen it eather the card is overheating or over clocked to far if it is over clocked. if it not overclocked then there something wrong with your gpu. most times now with flash and videos on my older 250 video card depeneding how the web page encodes it i might during the week get one or two message of the nividia driver stop responding but nothing of a hard lock up.
Well, I've been monitoring my GPU temps and they seem to be staying between 35-42 Celsius. I'm also on my stock GPU clock. In the past, there have been a few random times when the driver crashed and the screen went black. It would eventually recover but nevertheless.