Once in a while my monitors screen will 'flicker.' Its like the screen turns off then turns back on in the span of one second.

And also the screen seems to getting blurrier every day.
The blurriness is pretty much giving me a headache!

I have a Sony Trinitron E540 flatscreen. Ive had it about 4 years now.
Is my monitor dying? Can it be anything else like a video card problem or something?

Any help would be appreciated.