what did you upgrade about a month ago?
i brought a the cpu , graphic card, mobo and ram.but i just brought an new psu today and hopfully that will solve the problem
I have a 750W psu (which is overkill for my configuration) and I'm still having almost the same problems that you are. Happens on both Linux and Windows, so it's not software-related.
Only in my case, it only happens if I use a HDMI cable. Have you tried using a different type of cable to see if problem persists ? From what I read, DVI is the better solution.