Graphic issue with LOL and others.

Hello i like to get some info of whats going on with my computer. lately i had changed from windows 10 to windows 7 ultimate just because i prefer win 7 over 10. But now all the sudden after having a fresh start on my computer with the new operating system my screen has been showing artifacts or latency when i play league or use YouTube. When i just watch a video or play league the screen shows horizontal lines across my screen like its malfunctioning or something. When i play league my champ and everything seems to slow down and lag per say. I re position my graphic card, checked the adapter and even reinstall my Nvidia. I wonder if anyone has been having this problem too? It even shows in my browser when i just scrolling along and i see glitches in my screen.