Yep,
It's not the Yokes problem, but your OS. Likely the power management feature is turning the USB ports off.
In Win 7 I found that it was best to disable the power management feature on each USB Root Hub. To do that, go to Control Panel, Device Manager, open Universal Serial Hub Controllers (they should all expand), then right click on each. There will be a power management tab -- un-check the "Allow the computer to turn off this device to save power".
See if that does it....if not, go into your Power Management Plan (also in control panel), and create one with "High Performance Settings"....also, never let that sucker go to sleep or turn off the display (do it yourself...it's good exercise...the weight will just fall off). This should most likely correct this issue. Power management has its utility when you have a notebook, but doesn't particularly apply to a desktop.
Sometimes (usually) going green sucks and serves no valid purpose. If you have an ups on the system (like you should), it's the ups consuming the power, not the PC. Configure that to save the planet (like the planet cares).