Monitor sometimes goes blackfor a second. Huh?

[Unfocused]

Every now and then my screen goes black for a second (as if it was changing the refresh rate, for example). I recently changed my drivers to 91.47 (got 6800GS BTW) from the latest version, which has overclocking disabled. However, I had those 91.47 drivers before and they caused no problems, so I don't think it's a driver issue. Apart from that, my monitor and GPU seem to be working fine. Anyone had similar experience, perhaps?

 

[Operational]

Yea my friends CRT does the same about once every 45mins. I think it just happens when they get old.

 

[Unfocused]

Wtf, I just noticed, my GPU temperature is 67C and I have been browsing the net for half an hour (so no GPU intensive apps were running). That's probably it. But why the hell is the temp. so high? I cleaned the GPU a few weeks ago, so it can't be dust :?