Oh and one more thing, whenever i am on my main account trying to do any troubleshooting and stuff, the computer lags a lot on top of all the flickering and distortions and then i see that rotating rainbow thing (for approx. 6-7seconds) and then suddenly the display flashes (i mean is the display resolution/ colour suddenly gets lighter, just for a second) and the users login screen shows up.. This whole process repeats over and over again. This is extremely frustrating because this won't even let me do anything, all i see are weird lines and colour inversions on my top panel and whenever i try to open a file it just keeps loading and chrome takes forever to load..and before anything opens/showa, that rainbow cursor thing starts to rotate and the screen freezes, the colour of the screen suddenly flashes (only once) like a camera and then it takes me back to the login page. And, when i let my mac sit idle, i mean when i'm not touching any of the keys or the track pad; the display does still flicker but it stays logged in (doesn't log out on its own like in the earlier case). However, when i log in to the guest account everything works completely normal, there's absolutely no flickering and I'm not taken back to the login page which usually happens if i were using my admin/main account.
This has been all of the issues i have been facing lately. Its been bothering me a lot because i dont know what could have caused this problem when i no memory of ever having "broken" my mac. Could it be just a minor software bug? Please reply!!! Thank you.