Good points Vorpal, but i have tried everything you have mentioned, i tried to plug it to laptops as external screen, it shows up the same problem.
best quality i had with VGA cable, most terrible was with HDMI cable.

And i bought it on amazon 2 years ago, when i bought it i used only vga cable and used quite rarely. I somewhat noticed problem but wasn`t too interested in it, When time passed, and i kept grind more pokr (more time on PC) i started to understand, that something is not right, getting tired too fast. Then checked other LED screens around and saw difference. But it was too late to complain about faulty screen where i purchased it. Will try to fix it with local technicians or sell it. will some day.
All this posting in here was for a reason maybe someone had the same problems and sorted them out. But i guess this is a rare case when you just get unlucky and buy faulty stuff out there. Anyways will talk with tech guys nearby and post some updates here, how it went thorough. By myself, i am quite good at software and stuff. I have built couple PCs by myself, repairing others laptops now and then if needed. So i know a bit.
But this screen problem seems for me to have problem somewhere in depth of hardware, and i do not have knowledge and tools to fix it unfortunately.
Anyways, will update when this will be sorted.