I am using AMD Athlon processor 1.3 GHz, 256 MB RAM, Windows XP SP 2 desktop computer. The problem is if I scroll my web pages or watch full screen videos, there is a visible line moving at the centre of monitor and it reduces quality of video and slows web page scrolling. And lot of white small lines flickers when my pc boots, My mother board equipped with nvidia nforce videocard, when I reinstall my nvidia drivers the problem become worse, monitor turns itself off and on and sometimes not responding. So uninstalled nvidia drivers. I checked physical connections, everything seems fine, When I checked device manager, its not showing my monitor and video adapters. I need some help to resolve this, Thanks to everyone whoever gonna reply.