Asus Z97-A with 4790K

I built my father a system with these components back in 2014. After I built it, anytime I tried to run Prime95, I immediately got the error that a USB hub has exceeded the power recommendations and all of the USB ports stopped working. We never overclocked anything and he used it fine until he passed away in 2015. He didn't stress it like Prime in normal use. It's just been sitting in his computer room since he passed. I thought I'd mess with it yesterday. I unplugged all of the USB headers from the board and the only USB device I had was the Logitech adapter for the mouse and keyboard and it still happened. From what I have read, this can happen with no USB devices attached. I put Windows 10 on it and it still happens. This only happens with Prime95. I can run Realbench, OCCT and Linpack and it doesn't happen. I tried to run Linpack with AVX enabled and that lasted like 10 seconds before a core was hitting like 90 using a Thermalright cooler. What does Prime95 have to do with USB ports?

Have you updated drivers and motherboard drivers?

I did when I first built it with Win7. With Windows 10 Creator, all of the drivers are newer than what's available. I didn't even have to install drivers for the IME with Windows 10. The only driver it needed was for the Nvidia 760. I think the motherboard probably has been bad since I got it; throwing too much voltage into the USB header.

Have you tried flashing the bios to the latest version? Bios upgrade descriptors often state they are addressing USB issues. USB is not infrequently a problematic technology.

It had to be a short of some kind in the case. When I took it out of the case to test it and the 4790 to sell on Feebay, I never got the error again even before updating the BIOS. Both are long gone now to two different homes.