Why is my iMac's screen showing weird coloured squares?
My iMac was on sleep mode for about an hour or two. When I start using it for an hour, my mac hanged and the screen is displaying colourful pixelated squares.
My spotify was still playing as per normal, but I could not access to any thing on the screen, I can move and see my mouse cursor moving around but unable to click anything. I tried to force shut down and restart my computer, it was normal on the login screen but the boxes appear after approx 2-5 minute of usage each time.
I managed to backup my documents into my hard disk. While it was copying, it hanged with squares again but I heard the sound of the file being successfully copied into my hard disk.
I tried reformatting and installing the OS, nothing happened for a good 1-2 hour until the signing in of my Apple ID and it got hanged again.
My iMac is working well for the past 6-7 years , I know its old but its really treating me well till this weird looking squares start appearing.
I do not know what's wrong with it, which component is affecting this problem. I would like to know and get it fix asap!