Heatsink fan on desktop stop spinning

I am having problems on the heatsink fan on my computer. It suddenly stops spinning and my computer won't open anymore. I take the Power Supply Unit out and tried to do some testing through the multimeter. And the PSU failed. My computer's Mobo is ASUS P5K SE/EPU and I just purchase a new PSU with 600 watts on it. However, when I turned on my PC, it still encounters the same issue. What is wrong with my computer and does the new PSU compatible with my motherboard?
