Can't believe people here haven't stated to check the obvious first before going and saying to buy this, but that... You just recently changed your power supply, meaning you moved your system around quite a bit. You may have flipped it on its side rolled it over on the ground, who knows what you may have done to it but you did have to move it to change out the power supply. Then after restarting and playing around with settings you are now overheating, even back at default settings for your CPU. There's a chance it could be your motherboard, but it's always good to check a few things first.
With the computer shut down (of course), remove the heatsink. Clean off all the old thermal paste from CPU and the heatsink then re-apply thermal paste. A BB sized drop will be enough to spread on the CPU. DO not use your bare finger to spread the thermal paste. I've used a zip lock back wrapped around my index finger to spread thermal paste. Do NOT over do it as some thermal paste is conductive and can cause issues. Anyways, reinstall heatsink and make sure the clips are attached.