I tried it but it did not work. Still getting same grey horizontal patch on screen.

It's a transparent grey patch

No, it stopped doing that the next day after I put it in a dry place. It works but there is a constant horizontal gray patch visible that just won't go away. There is a line above patch the flickers, like some fluctuation, but the monitor works for hours as I run it without any shut down.

It worked like this even before I did the steps you suggested. There is no effect.

I am able to turn off and turn on the monitor with press of power button.

Sure. Another thing I would like to point out is there was little loosing CPU cable connected to monitor, sometimes I would experience diagonal flickering on screen which would go away after I adjusted the cable so it would not hang freely.

PCI

And

8MB

Are currently selected amd they were always selected.

Other options are:

Onboard/PEG

and

1MB.

I did it and there isn't any difference.

As I explained, even without CPU cable, this is the issue I'm getting just by plugging in power cable to monitor.

It has nothing to do with GPU

I tried it but stilll nothing happened.

I ran the test for nearly an hour, zero changes in the grey patch.

Thanks I will take it to a repair guy in that case, I will tell him about what you suggested.

Are you sure, there is no serious issue here?

I'm thankful for your help. One more thing I would like to add.

After repeating the steps you told me,I reset the Init display back to 8MB and I tried to run some graphic intensive programs like video games.

And I'm experiencing sudden shutdown unexpectedly. The window just shuts down itself when running games, but nothing happens when watching video or anything.

This was not happening earlier.

Windows shutdowns when running any game.

I tried to perform some graphic tests as I explained