Hood, I don't think either one of them really had that problem
. One of them reported on the SmoothStepper forum that changing the USB cable fixed his problem. Most folks don't follow any type of systematic method to troubleshoot a problem. They start clicking buttons and turning knobs and hope something changes. The last thing they remember touching then become the culprit. I'm as guilty of this as any, remember that I had issues with my SS that stemmed from me writing GCode by hand for the first time in years? I too was quick to jump on the last thing that changed in the system.
My point is that USB port don't just get shut off when the PC is in operation, that is NOT in the USB spec, nor would it make any sense. That being said I have seen strange issues with some motherboard's built in USB ports (all seemed to be USB 1.1 as well), they never lost power but they would not always appear as available to the system. I fixed it with a USB 2.0 PCI card.