Question my screen keeps flashing squares

[Junkers87d-5]

i will run a game and it will flash rainbow of colours i reinstalled the gpu and the problem subsided until i restarted my computer i tried to launch the game again and i see flashing lights

 

[Junkers87d-5]

it's a asus rog strix rx 560, it might be over heating so i turned up the fan speed on afterburner i do not have it overclocked at this time

 

[hang-the-9]

Start from the beginning, has this always happened? Does it happen in any game during testing?
Need to list full system specs including power supply brand and model.
You said not overclocked "at this time", so it was at some point? That can damage hardware even if you turn off the overclock when you start seeing issues.

Test the card in another system with a good power supply.