Okay sir....what likely will u suggest me to so now finally......?
Replace the hardware.Well - you can try
different gpu driver versions,updating firmware of the graphics card,reducing gpu core and memory overclock.If none of that helps, then it's a hardware problem for sure.
yeah...i am getting scrambled artifact lines when i start the pc while booting...You can try to reinstall the drivers or even a windows if You can and that's it, there's nothing more You can do.
Are You absolutely sure that temps are Okay under long stress? If so, then this GPU is probably dead and only warranty saves You. (heat can accumulate slowly in Your rig if You don't have good airflow, so the problem may happen after 1-2h of play? Maybe check again?)
When You start Your PC, do You ever see those artifacts on the screen? (i mean, when it's cold)