Well ,i think i must excuse from Sony. I just plugged a LCD monitor to my computer and BANG , the picture was shaking.
The problem isnt the Sony monitor nor my graphics card (i used that before with a perfect picture quality ).
It seems my mainboard(Asus P4P800) is causing somekind of picture quality problem (AGP port?). It's very interesting to see , an mainboard may cause an isolated picture quality problem. I will send it back to Asus.