monitor not working properly

[summak]

Hello Hardware Canucks,

I wanted some information and advice, on what is actually happening to my monitor.
All I can say, is that my half of the monitor is getting unresponsive, and back to responsive[for around 1 sec], its like a fade in and fade out effect. It just happened right now.

Here is a pic of it,
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the bottom black color part keeps coming and going, and when its gone, its not completely gone away, there is still little uncoloured part

And heres the screenshot of the desktop that i took with printscreen key
ImageShack® - Online Photo and Video Hosting

The monitor I am using is the dell ST2220L

Any help is really appreciated.

PS: if this needs to be posted in different thread, than please feel free to move so. Thank you